UC-NRLF 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

Class 


KNOCKS    AND    KINKS 


THE   POWER   HANDBOOKS 

The  best  library  for  the  engineer  and  the  man  \\ho  hopes 
to  be  one. 

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BY    PROF.    AUGUSTUS    H.    GILL 

Of  THE  MASSACHUSETTS  INSTITUTE  OF   TECHNOLOGY 

ENGINE   ROOM  CHEMISTRY 

BY  HUBERT   E.  COLLINS 

BOILERS  KNOCKS  AND  KINKS 

SHAFT  GOVERNORS  S  PUMPS 

ERECTING  WORK  SHAFTING,    PULLEYS    AND 

PIPES  AND  PIPING  BELTING 

BY  F.  E.   MATTHEWS 
REFRIGERATION.     (In  Preparation.) 


HILL    PUBLISHING    COMPANY 

505  PEARL  STREET,  NEW  YORK 

6  BOUVERIE  STREET,  LONDON,  E.G. 


THE    POWER    HANDBOOKS 

KNOCKS   AND    KINKS 

CAUSES,  DETECTION,  AND  CURE  FOR 
MANY  OF  THE  COMMONEST  OF  THESE 
TROUBLES  OF  THE  ENGINE-MAN 

PLAIN  DIRECTIONS  FOR  PREVENTION 
AND   REMEDY 


COMPILED  AND  WRITTEN 
BY 

HUBERT    E.    COLLINS 


1908 

HILL    PUBLISHING    COMPANY 
505  PEARL   STREET,  NEW  YORK 

6  BOUVERIE  STREET,  LONDON,  E.G. 
American  Machinist  —  Power  —  The  Engineering  and  Mining  Journal 


Copyright,  1908,  BY  THE   HILL  PUBLISHING   COMPANY 


All  rights  reserved 


Hill  Publishing  Company,  New  Tork,  U.S.A. 


CONTENTS 

CHAP.  PAGE 

I    CAUSES  OF  KNOCKS i 

II    CAUSES  OF  KNOCKS n 

HI.  CAUSES  OF  KNOCKS    . 21 

IV    CYLINDER  NOISES 28 

V    READY  DETECTION  AND  REMEDY 31 

VI  EFFECT  OF  INERTIA  OF  MOVING  PARTS     ....  55 

VII    SOME  CURIOUS  KNOCKS        61 

VIII  RIGGING  UP  TO  TURN  AND  REFIT  LARGE  PISTONS  — 

A  CRANK-PIN  TURNING  DEVICE        64 

IX  REPAIRING  A  BADLY  BROKEN  CYLINDER         ...  71 

X  REMOVING  A  TIGHT  PISTON-ROD  FROM  CROSSHEAD    .  74 

XI    SOME  MARINE  PRACTICE .     .  78 

XII  RE-BABBITTING  LARGE  ENGINE  BOXES      ....  82 

XIII  KEYING  UP  CRANK-PINS        84 

XIV  TESTING  FOR  A  LOOSE  CRANK-PIN 9° 

XV    Two  NARROW  ESCAPES        93 

XVI  SOME  PRACTICAL  KINKS        ....           ...  97 

XVII  How  A  NOISY  PISTON-VALVE  WAS  CURED       .     .     .  105 

XVIII  EMERGENCY  REPAIRS  AND  RUSH  JOBS       .     .     .     .  in 

XIX  TEMPORARY  REPAIR  TO  BROKEN  SHAFT    .     .     .     .  122 

XX  HANDLING  MACHINERY  WITHOUT  MARRING  IT    .     .  1 24 

XXI    To  FIND  DEAD  CENTER 126 


196490 


INTRODUCTION 

THIS  volume  of  The  Power  Handbooks  is  devoted  to 
"Knocks  and  Kinks."  The  kinks,  it  is  hoped,  will 
serve  to  eradicate  the  knocks.  For  a  long  time 
Power  has  made  a  feature  of  the  experience  of  prac- 
tical men  in  locating  knocks,  covering  the  common 
and  the  unusual  cases,  and  it  has  always  devoted 
some  space  to  little  kinks  which  enable  the  engineer  to 
master  many  of  the  vexatious  troubles  of  his  daily 
work. 

These  two  classes  of  articles  have  been  collected  and 
arranged  in  a  handbook  of  convenient  size  for  desk  or 
pocket,  and  with  the  other  books  of  this  series  will,  it 
is  hoped,  prove  of  value  to  the  operating  engineer. 

Every  engineer  has  been  taxed  to  the*  limit  of  his 
capacity,  at  some  time  or  other,  to  locate  "knocks." 
Most  engineers  have  had  to  call  in  help.  Some 
"knocks"  are  only  nerve-racking  but  the  majority 
of  them  indicate  operating  defects  and,  as  such, 
demand  immediate  attention  or  damage  will  result. 
The  compiler  acknowledges  his  indebtedness  to  various 
engineers  who  have  contributed  the  articles  to  Power 
which  form  the  bulk  of  this  book. 

HUBERT  E.  COLLINS. 

NEW  YORK,  August,  1908. 


OF   THE 

UNIVERSITY 

OF 


CAUSES  OF   KNOCKS ' 

WHILE  the  word  " knock"  has  many  and  varied 
applications,  its  meaning  in  this  book  is  confined  to 
that  species  of  knocks  with  which  every  operator  of  a 
steam  engine  is  familiar.  In  this  class  there  are  all 
degrees  of  knocks,  from  the  small  click  to  the  nerve- 
racking  (and  sometimes  engine-wrecking)  pound. 

When  a  knock  develops  in  an  engine  it  is  usually 
evidence  that  something  needs  looking  after;  and,  in 
general,  knocks  are,  or  should  be,  a  feature  for  elimina- 
tion. But  to  locate  and  remove  all  knocks  in/  an 
engine  is  not  always  as  simple  a  matter  as  might  be 
supposed.  One  reason  for  this  is  that  all -parts  of  the 
engine  are  intimately  connected,  arid  a  knock  produced 
at  one  point  is  transmitted  to  all  parts  of  the  machine. 
Sometimes,  due  to  the  form  or  material  of  some  par- 
ticular part  of  the  machine,  the  sound  will  appear  to 
originate  at  this  point,  when  in  fact  it  may  be  pro- 
duced at  some  distance  from  it.  The  principle  is  the 
same  as  that  involved  when  a  vibrating  tuning-fork  is 
held  against  a  table. 

Generally  speaking,  a  knock  in  an  engine  is  the 
result  of  lost  motion  between  two  parts.  It  therefore 

1  Contributed  to  Power  by  C.  J.  Larson. 

I 


2  KNOCKS  AND    KINKS 

follows  that  every  bearing  in  the  machine  may  be  the 
occasion  for  a  knock,  provided  sufficient  looseness  be 
afforded  and  that  there  is  a  reversal  of  forces  acting. 
All  bearings  that  have  motion  must  of  necessity  have 
some  clearance  between  the  parts,  otherwise  there 
would  be  undue  friction  and  heating.  This  clearance, 
when  not  excessive,  is  filled  with  oil  which  lubricates 
the  parts  and  acts  as  a  cushion  between  the  metallic 
surfaces,  reducing  or  removing  the  tendency  to  knock. 

In  nearly  all  bearings  of  a  reciprocating  engine  there 
is  a  reversal  of  pressure  at  every  stroke.  The  natural 
place  to  look  for  a  knock,  therefore,  is  in  those  bearings 
where  pressures  are  greatest  and  where  one  would 
expect  the  most  wear,  viz.,  the  main  bearing,  crank- 
pin,  crosshead  pin  and  slides.  These  knocks  are 
usually  easily  located,  while  the  engine  is  running, 
by  flooding  each  bearing  in  turn  with  oil.  When  a 
bearing  has  comparatively  little  lubrication  the  knock 
will  be  sharp  and  metallic,  but  when  flooded  with  oil 
the  excess  is  squeezed  out  from  between  the  bearing 
surfaces  and  cushions  the  blow,  reducing  the  knock 
to  a  slapping  sound.  Ordinarily,  therefore,  simply 
keying  up  the  bearing  in  question  should  remove  the 
knock. 

In  line  with  the  above,  an  engine  which  is  quite 
noisy  when  supplied  with  oil  in  drops  may  often  run 
beautifully  when  lubricated  by  means  of  a  pressure  or 
gravity  system.  The  latter  method,  we  are  disposed 
to  say,  is  the  sensible  way  to  lubricate  an  engine  of 
any  considerable  size,  at  least.  Many  high-speed  en- 
gines are  lubricated  by  splashing  the  oil  in  the  crank- 


CAUSES   OF   KNOCKS  3 

case,  and  bearings  are  often  run  loose  without  knocking, 
for  the  reason  that  they  are  always  flooded  with  oil. 

The  proper  adjustment  of  the  engine  valves  may 
have  a  great  deal  to  do  with  quiet  running.  The  object 
is  to  have  the  thrust  at  different  bearings  reversed  as 
gradually  as  possible.  Unless  an  engine  has  good 
steam  distribution  it  is  often  useless  to  attempt  to  get 
it  to  run  quietly.  It  does  not  necessarily  follow  that 
an  engine  with  badly  adjusted  valves  must  knock,  but 
the  chances  for  smooth  running  are  certainly  much 
fewer.  This  is  especially  true  in  the  higher-speed 
engines.  The  first  step,  therefore,  toward  removing 
knocks  from  an  engine,  if  there  is  any  doubt  about  the 
setting  of  valves,  is  to  apply  the  indicator. 

CAUSES  OF  SOME  KNOCKS 

Figure  I  shows  a  pair  of  indicator  diagrams  taken 
from  a  small  Corliss  engine  having  a  very  bad  knock 


FIG.    I 


in  the  head  end.  Many  attempts  at  keying  failed  to 
improve  matters,  when  the  cause  of  knock  was  instantly 
located  with  the  indicator.  The  engine  had  always 


4  KNOCKS   AND    KINKS 

run  well  until  one  night  the  engineer  decided  to  examine 
the  valves.  In  replacing  them  he  accidentally  got  the 
head-end  exhaust  valve  entered  on  the  T  head  of  the 
valve-stem  upside  down. 

By  referring  to  Figs.  2,  3,  4  and  5,  it  will  be  seen 


FIGS.    2,  3,  4,   5 

that  when  a  horizontal  engine  runs  "over,"  the  thrust 
from  the  connecting-rod  is  downward,  except  at  the 
instant  the  engine  is  passing  centers,  when  the  cross- 
head  has  nothing  but  its  weight  to  keep  it  firmly 
against  the  slide.  Should  the  compression  be  exces- 
sive, however,  it  can  be  seen  that  the  crosshead  might 


CAUSES   OF   KNOCKS  5 

be  lifted  from  the  slide  toward  the  end  of  each  stroke. 
Normally,  therefore,  there  should  be  no  knock  between 
the  crosshead  and  the  slide,  even  though  the  former 
has  a  chance  to  lift;  but  since  from  any  variation  in 
speed  or  pressure  this  might  occur,  it  is  not  safe  to  run 
with  excessive  clearance  between  the  top  slide  and 
crosshead.  But  when  the  engine  runs  "under,"  con- 
ditions are  opposite.  The  crosshead  is  then  forced 
against  the  top  slide,  except  when  at  centers,  and  then 
the  crosshead  tends  to  drop  onto  the  bottom  slide  from 
its  own  weight.  It  is  necessary,  therefore,  to  adjust 
the  bottom  crosshead  shoes  quite  snugly  when  the 
engine  runs  "  under,"  or  there  will  be  a  knock  at  every 
center.  This  knock  is  not,  however,  as  sharp  as  one 
produced  at  any  of  the  other  bearings  referred  to,  since 
the  pressure  per  unit  surface  of  the  crosshead  shoes  is 
comparatively  small. 

In  vertical  engines,  direction  of  rotation  and  weight 
of  crosshead  have,  of  course,  no  effect  as  far  as  pro- 
ducing knocks  between  the  latter  and  its  slides  is 
concerned.  Vertical  engines  of  the  direct-connected 
type  usually  have  the  fly-wheel  and  the  revolving 
member  of  the  generator  mounted  on  the  shaft  be- 
tween the  engine  bearings,  and  the  total  weight  of 
the  rotating  parts  generally  becomes  so  heavy  that 
the  shaft  is  not  lifted  from  its  bottom  bearing  by  the 
upward  pressure  on  the  piston.  It  is  therefore  desir- 
able to  allow  an  unusual  amount  of  clearance  between 
the  shaft  and  the  top  bearing,  as  this  permits  a  freer 
distribution  of  the  lubricating  oil. 

If,  therefore,   the  pressure  in  the  cylinder  should 


6  KNOCKS   AND   KINKS 

from  any  cause  be  increased  to  a  point  sufficient  to 
lift  the  shaft,  the  result  will  be  a  heavy  pound  when  it 
returns  to  the  bottom  bearing.  The  above  occurs  in 
case  water  accumulates  in  the  bottom  end  of  the 
cylinder.  Should  the  receiver  pressure  in  a  compound 
engine  become  excessive  the  shaft  will  lift;  the  same 
thing  may  also  occur  from  excessive  compression. 
Suppose  the  engine  is  running  condensing,  with  the 
valves  adjusted  properly  for  that  condition,  then  under 
non-condensing  conditions  the  compression  would  be 
much  too  great  and  tend  to  lift  the  shaft  and  cause 
pounding. 

If  the  weight  on  the  bearings  is  not  in  excess  of  the 
upward  force  on  the  piston  the  bearing  caps  of  vertical 
engines  must,  of  course,  be  set  up  snugly.  A  good 
example  of  the  latter  case  is  the  marine  engine,  which 
has  no  fly-wheel,  and  the  weight  on  the  bearings  is 
that  of  the  shaft  only. 

Knocks  in  the  valve-gear  can  be  located  by  flooding 
with  oil,  as  described.  The  knock  produced  by  an 
eccentric-strap  which  is  too  loose  usually  has  a  slapping 
sound  unless  the  speed  be  high  or  lost  motion  great. 
The  reason  for  this  is  that  the  surfaces  between  the 
eccentric  and  strap  are  .large  in  proportion  to  the 
forces  transmitted.  In  taking  up  an  eccentric-strap, 
care  needs  to  be  exercised  not  to  get  it  too  tight,  for 
while  the  pressure  per  unit  of  area  is  small,  the  sliding 
velocity  is  usually  high.  This  is  especially  true  in 
direct-connected  engines,  where  the  shaft  is  necessarily 
of  large  diameter. 

In  some  single-valve  engines  the  eccentric-rod  con- 


CAUSES    OF    KNOCKS  7 

nects  direct  to  the  valve-stem,  making  only  one  bearing 
at  this  point  and  consequently  only  one  chance  for 
knock.  But  very  often  it  is  necessary  to  transfer  the 
motion  of  the  eccentric  by  means  of  rocker-arms  into 
line  with  the  valve.  This  offset  in  motion  is  a  neces- 
sary evil  since  it  multiplies  the  number  of  bearings, 
and,  as  there  must  of  necessity  be  some  clearance  in 
each,  the  aggregate  may  result  in  a  number  of  knocks 
occurring  simultaneously  on  the  reversal  of  motion, 
which  sounds  like  one  heavy  knock. 

Large  engines  often  have  the  carrier  arms  and 
brackets  cast  hollow,  for  the  purpose  of  combining 
lightness  with  rigidity.  This  is  excellent  from  an 
engineering  point  of  view,  but  a  large  amount  of 
surface  is  presented  in  these  parts  which  greatly 
intensifies  the  sound  of  any  existing  knock. 

Some  years  ago  a  large  Corliss  engine,  which,  while 
it  ran  well  and  gave  good  service,  had  what  seemed  a 
fearful  pound  about  the  middle  of  each  stroke.  Many 
efforts  had  been  made  to  locate  and  remedy  the 
trouble  without  success,  and  it  was  finally  concluded 
that  the  cylinder  was  not  in  line  with  the  slide  and 
that  the  thump  was  caused  by  the  piston  striking  the 
side  of  the  cylinder.  The  piston  was  accordingly  re- 
moved and  a  line  passed  through  the  engine,  but  it 
was  found  in  perfect  alinement. 

It  was  a  double-eccentric  machine,  and  while  oper- 
ating condensing,  the  exhaust  eccentric  would  be  set 
somewhat  in  advance  of  the  steam  eccentric.  It  had 
been  necessary  to  run  non-condensing  for  some  time 
due  to  lack  of  water,  and  the  exhaust  eccentric  had 


8  KNOCKS    AND    KINKS 

been  set  back  to  get  the  proper  steam  distribution  for 
the  latter  condition.  This  happened  to  leave  the  two 
eccentrics  moving  in  unison. 

There  were  two  bearings  for  each  carrier-arm  stud, 
and  one  for  each  eccentric-rod  and  wrist-plate  connec- 
tion, making  eight  bearings  in  all.  It  had  no  doubt 
been  observed  that  these  various  bearings  were  not 
particularly  tight,  but  it  had  occurred  to  no  one  that 
there  might  be  eight  distinct  knocks,  all  coming  at  the 
same  instant,  and  all  receiving  the  benefit  of  the 
resonance  effect  of  the  hollow  arms  and  brackets. 
After  these  bearings  had  been  carefully  taken  up  and 
provision  made  for  a  better  distribution  of  oil,  the 
engine  started  off  quietly,  and  every  one  concerned 
said,  "Well,  did  you  ever?" 

KNOCKS  IN  SHAFT  GOVERNORS 

Nearly  all  high-speed  and  many  of  the  so-called 
moderate-speed  engines  of  the  automatic  cut-off  class 
are  provided  with  some  form  of  shaft  governor.  The 
speed  of  the  engine  is  controlled  by  shifting  the  position 
of  the  steam  eccentric,  either  as  to  angle  of  advance  or 
as  to  throw,  and  sometimes  by  a  combination  of  both 
these  movements.  Knocks  sometimes  develop  in  these 
governors  which  are  not  easily  located  since  the  parts 
are  revolving  within  a  wheel  and  consequently  difficult 
to  study  while  in  motion.  There  are  several  reasons 
for  these  knocks.  Sometimes  the  bearings  in  the  gov- 
ernor do  not  receive  proper  lubrication.  These  parts 
should  be  provided  with  some  means  of  certain  lubri- 


CAUSES   OF   KNOCKS  9 

cation.  Where  an  engine  runs  continuously  for  long 
periods  the  governor  bearings  soon  become  dry  and 
bind;  the  oil  which  was  applied  before  starting  is 
thrown  off  by  centrifugal  force,  and  it  is  an  uncertain 
method  to  try  periodically  to  oil  the  governor  with  a 
squirt-can. 

The  fact  that  bearings  are  dry  would  often  cause  a 
knock  of  itself;  but  most  shaft  governors  are  very 
sensitive  as  to  speed,  and  in  consequence  of  this  feature 
they  often  tend  to  move  to  extremes  when  any  sticki- 
ness exists  in  the  bearings  of  the  governor  arms.  We 
have  seen  shaft  governors  which  would  allow  the 
weights  to  rapidly  alternate  between  the  positions  for 
no  load  and  maximum  load,  striking  the  stops  at  both 
ends  of  their  travel  and  producing  knocks.  This  may 
occur  so  rapidly  as  to  cause  a  surprisingly  small 
variation  in  the  speed  of  the  engine. 

Knocks  will  often  be  produced  in  the  shaft  governor 
on  account  of  excessive  strains  upon  the  various  parts. 
This  condition  prevails  when  the  valve  or  valves  move 
too  heavily,  as  from  lack  of  lubrication.  When  the 
boiler  primes,  the  oil  will  be  washed  off  the  valve 
faces,  causing  undue  friction,  and  if  grit  and  particles 
of  scale  are  carried  over  with  the  water,  so  much  the 
worse.  The  result  of  the  latter  condition  is  most  pro- 
nounced in  an  engine  equipped  with  a  snugly  fitting 
balanced  valve.  The  effect  of  the  sticking  valve  in 
the  case  of  a  single-valve  engine  is  to  force  the  governor 
into  the  position  for  minimum  cut-off,  while  the  gov- 
ernor, responding  to  decrease  in  speed,  struggles  for 
the  opposite.  This  condition,  while  tending  to  make 


10  KNOCKS   AND    KINKS 

the  governor  weights  strike  the  stops,  will  also  produce 
knocking  in  all  the  bearings  through  which  the  force 
is  transmitted  to  the  valve. 

Sometimes  a  single-valve  automatic  engine  may  run 
quietly,  with  bearings  and  pins  loose,  at  one  steam 
pressure,  but  knock  fiercely  when  the  pressure  is 
reduced.  This  looks  like  a  paradox,  but  it  is  not  when 
one  analyzes  the  situation.  In  this  type  of  engine  the 
cut-off  is  shortened  by  decreasing  the  travel  of  the 
valve,  while  the  lead  remains  practically  constant. 
This  is  accomplished  by  moving  the  eccentric  across 
the  shaft  in  a  direction  which  corresponds  to  a  change 
of  throw  and  angular  advance.  But  as  the  cut-off  is 
shortened  the  exhaust  closure  also  comes  earlier,  and 
vice  versa.  As  the  steam  pressure  drops,  the  cut-off 
becomes  later  and  consequently  compression  is  reduced. 
Therefore,  the  real  cause  of  knocking  is  lack  of  com- 
pression necessary  to  overcome  the  inertia  of  the 
reciprocating  parts. 


II 

CAUSES  OF   KNOCKS1 

A  COMMON  method  of  attaching  a  slide  or  piston- 
valve  to  its  stem  is  by  means  of  two  nuts  jammed 
together  at  either  side  of  the  valve.  It  is  not  an  un- 
usual occurrence  to  have  these  nuts  work  loose  and 
allow  clearance  for  the  valve  between  the  nuts  and 
cause  a  knock  at  this  point.  This  condition  should  be 
quickly  detected  by  the  action  of  the  engine,  as  it 
means  a  reduced  valve  movement  and  irregular  steam 
distribution.  If  the  engine  were  running  non-con- 
densing, the  above  derangement  would  readily  be 
noticeable  by  the  uneven  exhausts. 

There  is  a  possibility  for  knocks  to  exist  in  almost 
any  form  of  engine  valve.  The  type  of  valve  which  is 
least  liable  to  produce  a  knock  is  the  piston-valve,  but 
even  in  this  there  may  be  the  click  of  the  packing 
rings.  This  may  be  caused  by  the  rings  fitting  the 
grooves  too  loosely  and  rattling  back  and  forth  as 
the  valve  reverses  its  motion,  or  it  may  be  due  to  the 
rings  being  slightly  collapsed  from  a  sudden  increase 
in  pressure  in  the  port  surrounding  the  rings.  It  will 
be  observed  that  all  the  surface  of  the  face  of  these 
rings,  except  that  covered  by  the  ribs  on  the  port,  is 

1  Contributed  by  C.  J.  Larson. 


^ 

OF    THE 

UNIVERSITY 


12  KNOCKS   AND   KINKS 

exposed  to  the  direct  pressure  of  the  steam  during  the 
period  that  each  ring  is  crossing  the  port  opening. 

KNOCKS   CAUSED   BY   VALVES   LIFTING   FROM   SEATS 

In  all  forms  of  steam-valves  free  to  lift  from  their 
seats  a  knock  will  result  whenever  the  pressure  be- 
comes greater  in  the  cylinder  than  in  the  steam-chest. 
This  condition  will  arise  from  water  in  sufficient  quan- 
tities to  fill  the  clearance  space,  or  from  excessive 
compression  due  to  faulty  valve  setting.  The  valve 
will  lift  from  its  seat  as  the  piston  approaches  the  end 
of  the  stroke,  acting  as  a  safety  valve;  then  the  instant 
the  piston  starts  forward  the  pressure  drops  and  the 
valve  returns  to  its  seat  with  a  slam.  It  is  usual  to 
make  valves  so  that  they  may  lift  a  limited  amount 
and  act  as  reliefs,  in  case  of  emergency  from  water, 
but  they  should  never  be  permitted  to  lift  from  steam 
pressure,  ordinarily.  When  the  compression  is  suffi- 
cient to  force  a  regular  slide  valve  from  its  seat,  serious 
loss  of  steam  results,  as  when  the  valve  is  not  in  con- 
tact with  its  seat,  a  direct  communication  between  the 
steam-chest  and  the  exhaust  port  is  established.  In 
engines  with  separate  steam  and  exhaust  valves,  part 
of  the  steam  filling  the  clearance  space  will  be  forced 
into  the  steam-chest. 

If  the  steam-valves  are  set  to  open  so  early  that  full 
initial  pressure  is  obtained  before  the  piston  has 
reached  the  end  of  the  stroke,  the  result  is  much  the 
same  as  if  the  compression  were  excessive.  The  result- 
ing knock,  however,  is  more  in  the  nature  of  a  clatter 


CAUSES   OF.  KNOCKS  13 

of  the  valve,  for  since  the  valve  is  already  open  it  does 
not  have  to  be  forced  from  its  seat,  but  the  current  of 
steam  being  forced  back  into  the  steam-chest  until  the 
piston  reaches  the  end  of  the  stroke  will  make  the  valve 
rattle  on  its  seat. 

It  may  be  said  here  that  excessive  lead  is  often 
responsible  for  knocks  in  the  various  bearings,  since  it 
applies  a  heavy  pressure  suddenly  against  the  piston 
at  a  time  when  it  has  considerable  velocity. 

Where  independent  exhaust  valves  are  used,  there 
may  be  clattering  of  these  valves  under  certain  condi- 
tions. If  the  engine  operates  non-condensing  and  the 
cut-off  is  very  early,  the  steam  will  expand  considerably 
below  the  atmospheric  pressure.  The  result  is  that 
toward  the  end  of  the  stroke,  and  before  the  exhaust 
valve  has  opened,  the  steam  in  the  exhaust  pipe  will 
lift  the  valves,  rush  into  the  cylinder  and  cause  a 
rattling  of  the  valves.  This  will  occur  with  any  type 
of  independent  exhaust  valve  which  is  free  to  lift  from 
its  seat.  With  Corliss  valves,  it  should  not  occur  in  a 
new  engine,  as  the  valves  fit  the  ports  quite  snugly, 
but  it  may  always  be  noticed  in  an  old  Corliss  engine 
where  the  valves  and  seats  are  worn  down  even  a 
small  amount. 

Knocks  often  occur  from  Corliss  exhaust  valves 
having  end  play.  It  would  at  first  seem  that  there 
should  be  no  occasion  for  the  valves  to  move  endwise, 
even  if  they  have  clearance  in  that  direction.  It  is 
not  safe  to  make  the  valves  too  snug-fitting  endwise, 
especially  in  large  engines,  since  the  valve,  being  lighter 
than  the  walls  of  the  chamber  in  which  it  turns,  will 


14  KNOCKS   AND   KINKS 

expand  faster,  and  if  no  clearance  at  the  ends  is  allowed, 
an  accident  may  result  in  starting  the  engine,  unless  all 
the  parts  have  acquired  an  equal  temperature. 

These  valves  are  round  and  fit  the  chamber  quite 
snugly  for  some  distance  at  each  end.  One  end  is 
slotted  for  the  stem,  with  the  result  that  there  is  more 
waste  space  for  steam  than  at  the  back  end.  Now, 
when  the  exhaust  valve  opens,  the  steam  in  this  waste 
space  expands  and  drives  the  valve  against  the  back 


FIG.   6 

bonnet,  sometimes  causing  a  very  severe  knock,  even 
when  the  clearance  is  small.  Then,  when  the  valve 
has  closed  and  steam  is  admitted,  the  small  space  at 
the  back  end  will  accumulate  pressure  faster  than  the 
larger  space  at  the  stem  end,  and  the  valve  will  be 
driven  back.  The  end  knock  of  an  exhaust  valve  can 
be  distinctly  felt  by  holding  any  object  firmly  against 
the  back  bonnet. 

The  quickest  way  to  correct  such  a  knock  is  to  cut 
passages  for  the  steam  in  the  ends  of  the  valve  large 
enough  so  that  the  pressure  will  always  be  the  same  at 
the  ends  of  the  valves  as  in  the  cylinder.  Fig.  6  shows 


CAUSES   OF   KNOCKS  15 

a  Corliss  exhaust  valve,  with  channels  cut  at  A  and  B 
for  removing  this  knock. 

VALVES  CHATTERING  ON  SEATS 

Almost  equally  annoying  as  valves  knocking  is  their 
chattering  on  their  seats.  This  is  caused  by  lack  of 
lubrication,  or  too  much  spring  in  the  various  parts 
operating  the  valves,  allowing  them  to  move  on  their 
seats  by  jumps,  as  it  were.  Sometimes  part  of  this 
chattering  is  caused  by  the  valve  motion  having  loose 
joints,  giving  the  valve  a  jerky  motion.  In  some  cases 
it  will  be  found  that  while  ample  oil  is  being  supplied 
it  does  not  find  its  way  between  the  valve  and  seat. 
Grooving  the  face  of  the  valve  or  seat  will  often  greatly 
aid  the  distribution  of  the  oil.  In  large  engines,  excel- 
lent results  have  been  obtained  by  grooving  the  valve- 
seat  and  piping  the  oil  into  grooves  under  the  valve, 
when  no  amount  of  oil  sprayed  into  the  steam  would 
stop  the  grating  of  the  valves.  An  inexperienced 
person  might  mistake  this  chattering  of  the  valves  for 
the  piston  "grunting  for  grease,"  but  the  former  can 
readily  be  detected  by  the  slight  trembling  of  the  valve 
connections. 

Should  the  piston  become  loose  on  the  rod,  even  a 
very  small  amount,  a  heavy  knock  will  result,  which 
usually  gets  worse  rapidly.  The  most  common  prac- 
tice is  to  have  the  piston  held  by  a  nut  on  the  rod. 
This  may  not  have  been  tightened  sufficiently,  allowing 
it  to  back  off.  It  also  happens  that  pistons  are  loosened 
by  water  in  the  cylinder. 


i6 


KNOCKS   AND    KINKS 


A  peculiar  case  of  knock  was  recently  found  in  the 
high-pressure  piston  of  a  vertical  cross-compound  en- 
gine of  2500  horse-power.  The  engine  would  pound 
fearfully  on  the  bottom  center,  sometimes  every  revo- 
lution, then  at  times  run  quietly  for  some  seconds,  and 
at  other  times  it  would  pound  every  other  revolution 
for  minutes  at  a  time,  reminding  one  of  the  exhaust 
from  a  "hit-and-miss"  gas  engine.  The  nut  on  the 
piston-rod  had  been  tried  several  times,  but  it  seemed 


FIG.    7 


tight.  Fig.  7  shows  the  detail  of  the  construction.  It 
happened  that  there  was  insufficient  thread  on  the 
piston-rod  and  that  the  bottom  side  of  the  nut  did  not 
actually  bear  on  the  piston.  Since  the  nut  was  coun- 
terbored  into  the  piston,  one  could  not  see  when  it 
came  in  contact,  and  its  tightness  on  the  thread  was 
mistaken  for  its  bearing  on  the  piston. 

It  will  be  seen  that  the  rod  is  tapered  in  the  piston, 
and  apparently  on  some  down  strokes  the  piston  would 
be  driven  so  firmly  onto  this  taper  that  it  was  not 
removed  when  steam  was  admitted  on  the  bottom 


CAUSES   OF   KNOCKS  17 

center.  Whenever  the  piston  stuck  there  was  no  pound 
of  course. 

In  built-up  pistons,  when  a  follower  is  secured  with 
studs,  there  is  always  the  possibility  of  a  stud  backing 
out  and  striking  the  cylinder-head.  Cases  have  been 
known  where  through  error  in  machine  work  the  junk 
ring  was  not  clamped  firmly  between  the  shoulder  on 
the  piston  body  and  the  follower.  This  will  cause  the 
junk  ring  to  knock  against  these  parts  as  the  piston 
reverses  its  stroke. 

If  the  packing  ring  travels  over  the  counterbore  in 
the  cylinder  to  any  extent,  a  part  of  its  external  surface 
is  exposed  to  the  initial  pressure  at  the  instant  that 
the  piston  is  at  the  end  of  the  stroke.  The  result  is 
that  the  ring  is  slightly  collapsed,  and  as  soon  as 
the  piston  moves  forward  the  ring  expands  against  the 
cylinder  walls  with  a  sharp  click.  This  action  of  the 
packing  ring  in  the  piston  is  identical  with  that  de- 
scribed previously  in  connection  with  rings  in  piston 
valves.  There  will  also  be  the  same  knock  in  pistons 
as  in  piston-valves  if  the  rings  fit  the  grooves  loosely, 
except  that  since  the  velocities  of  pistons  are  so  much 
higher,  the  knock  resulting  from  a  given  clearance  will 
be  correspondingly  greater. 

A  common  method  of  attaching  the  piston-rod  to  the 
crosshead  is  by  means  of  a  thread  and  jam-nut.  This 
arrangement  affords  an  easy  means  for  re-adjusting 
the  clearance  in  the  cylinder,  but  if  the  jam-nut  should 
loosen,  the  rod  may  screw  in  or  out  of  the  crosshead, 
and  allow  the  piston  to  knock  one  of  the  cylinder-heads. 
Any  striking  of  the  piston  or  the  studs  against  the 


i8  KNOCKS   AND   KINKS 

cylinder-head  can  be  readily  felt,  by  holding  any  object, 
as  the  end  of  a  lead  pencil,  against  the  cylinder-head. 
Whenever  any  knock  occurs  within  the  cylinder  it 
should  be  investigated  immediately  and  its  exact  cause 
ascertained  as,  if  the  piston  is  striking  the  cylinder-head, 
it  not  only  may  wreck  the  engine  but  cause  loss  of  life, 

ENGINES  "Our  OF  LINE"  CAUSE  KNOCKS 

A  great  many  knocks  may  exist  from  an  engine  being 
out  of  line.  This  term,  however,  is  somewhat  ambig- 
uous. When  the  shaft  is  not  at  right  angles  to  the 
center  line  of  the  cylinder  the  engine  is  said  to  be 
"out  of  line/'  but  the  same  expression  is  used  when 
the  cylinder  and  slide  are  not  in  line,  or  when  the  path 
of  the  connecting-rod  is  not  in  line  with  the  cylinder 
and  slide.  This  latter  condition  would  prevail  if  the 
shaft  were  moved  endwise  in  the  bearings. 

Figure  8  shows  a  shaft  out  of  right  angles  with  the 
cylinder.  Since  the  thrust  from  the  connecting-rod 
does  not  bear  squarely  onto  the  crank-pin,  it  follows 
that  on  the  forward  stroke  the  crank  brasses  will  bear 
sidewise  against  the  face  of  the  crank,  while  on  the 
return  stroke  this  side  thrust  will  come  on  the  head  of 
the  crank-pin.  Therefore,  if  the  brasses  have  any  side 
clearance,  a  knock  will  result  from  the  side  slap  of  the 
rod.  It  also  follows  that  if  the  shaft  is  not  at  right 
angles  to  the  engine  the  connecting-rod  will  be  out  of 
line  with  the  cylinder  and  slide.  This  amount  is 
greatest  at  the  centers,  or  where  the  pressures  are 
reversed,  consequently  the  evil  that  results  is  greatest. 


CAUSES   OF   KNOCKS 
c||A 


19 


FIG.    8 


20  KNOCKS  AND   KINKS 

The  effect  of  the  connecting-rod  being  out  of  line  with 
the  slide  is  a  tendency  to  produce  a  knock  from  the 
crosshead  being  forced  sidewise  in  opposite  directions 
at  each  center,  and  also  to  cause  side  knocking  of  the 
connecting-rod  in  the  crosshead.  The  reason  for  this 
will  be  understood  by  referring  to  Fig.  8,  where  A  B 
represents  the  center  line  of  the  cylinder,  and  C  D  the 
path  of  the  crank-pin,  with  the  shaft  out  of  line. 

When  the  cylinder  is  not  in  line  with  the  slide 
sidewise  there  is  a  tendency  to  knock  at  the  crosshead 
on  the  head  end  of  the  stroke,  similar  to  that  just 
described  above.  Also  if  the  piston  is  not  snug-fitting 
in  the  cylinder  bore,  it  will  slam  against  the  side  of  the 
cylinder  and  produce  a  knock.  This  is  especially  true 
in  vertical  engines,  where  the  piston  is  unstable  and 
responds  to  even  a  small  force  sidewise.  The  reason 
that  there  will  be  no  knock  at  the  head  end  in  this 
case  is  that  the  cylinder  is  in  line  at  that  end.  This 
is  illustrated  in  Fig.  8,  where  the  cylinder  not  in 
alinement  is  shown  in  dotted  outline. 

Another  serious  result  in  horizontal  engines  from  the 
cylinder  being  out  of  line  is  excessive  wear  on  the 
piston  and  cylinder.  When  the  engine  runs  in  this 
condition  the  piston  has  a  slightly  rocking  motion,  the 
effect  of  which  is  to  wear  the  piston  most  on  its  edges 
and  destroy  its  true  cylindrical  form,  with  the  result 
that  the  piston  is  deprived  of  a  large  amount  of  surface 
for  its  support,  and  consequently  the  pressure  per  unit 
of  surface  becomes  high  and  the  wear  excessive.  This 
trouble  may  also  result  from  the  crosshead  not  being 
adjusted  in  the  center  of  the  slides. 


Ill 

CAUSES  OF   KNOCKS1 

IF  the  cylinder  of  a  vertical  engine  be  so  designed 
that  a  large  portion  of  the  face  of  the  piston  is  exposed 
to  the  steam  port  while  the  engine  is  on  the  center, 
and  if  the  piston  does  not  fit  the  cylinder  snugly,  a 
knock  may  result  from  the  piston  being  suddenly 
forced  against  the  opposite  side  of  the  cylinder  from 
the  impact  of  the  inrushing  steam.  This  trouble  is 
often  encountered  with  high-speed  engines,  and  may 
sometimes  be  overcome  by  giving  the  engine  more 
compression.  The  effect  of  this  is  to  reduce  the 
velocity  of  the  steam  in  the  port  at  the  instant  of 
valve  opening.  In  horizontal  engines  where  the  steam 
ports  are  on  the  side  of  the  cylinder  this  difficulty  may 
also  be  met  with,  but  it  can  manifestly  not  occur 
where  the  steam  is  admitted  on  the  top  side,  as  in  a 
standard  type  of  Corliss  cylinder. 

A  condition  which  may  exist  in  vertical  engines  and 
which  is  quite  analogous  with  that  of  a  horizontal 
engine  having  the  shaft  out  of  line,  is  that  resulting 
from  deflection  of  the  shaft  from  the  weight  of  the 
fly-wheel  and  generator.  To  one  who  has  not  had 
occasion  to  observe  the  same,  it  would  appear  that  a 

1  Contributed  to  Power  by  C.  J.  Larson. 
21 


22  KNOCKS   AND    KINKS 

steel  shaft  two  or  three  feet  in  diameter  could  not 
possibly  spring  an  appreciable  amount  from  any 
weight  which  the  bearings  would  carry.  Bur'  this  is 
not  the  case.  The  amount  of  this  shaft  deflection  is 
sufficient  in  all  direct-connected  units  to  be  carefully 
allowed  for  in  erecting  the  machine. 

It  can  readily  be  seen  that  if  the  shaft  sags  between 
bearings,  the  path  described  by  the  center  of  the 
crank-pin  will  not  be  in  a  truly  vertical  plane,  but  will 
incline  toward  the  fly-wheel  side  of  the  engine.  There- 
fore, in  order  to  have  an  engine  of  this  description  in 
perfect  line  as  regards  its  shaft,  the  frames  and  cylinder 
should  be  set  sufficiently  out  of  plumb  to  make  their 
center  line  coincide  with  the  plane  of  the  crank-pin 
travel.  If  this  is  not  done  there  will  be  the  tendency 
to  knock,  as  previously  described  in  connection  with  a 
horizontal  engine  having  the  shaft  out  of  line. 

If  from  any  cause  the  crank-pin  is  not  parallel  with 
the  shaft,  the  crank-pin  brasses  will  knock  sidewise. 
The  point  in  the  stroke  at  which  the  knock  occurs  will 
be  determined  by  the  direction  in  which  the  pin  is 
inclined.  It  will  be  found  impossible  to  key  the  crank 
brasses  anywhere  near  snugness  without  heating,  and 
this  condition  will  also  cause  a  side  knock  at  the  cross- 
head  pin,  if  there  is  any  clearance.  The  crosshead  end 
of  the  connecting-rod  will  be  thrown  from  side  to  side. 
The  crank-pin  can  be  tested  for  parallelism  with  the 
shaft  by  disconnecting  the  rod  at  the  crosshead,  slowly 
revolving  the  engine,  and  noting  any  side  movement 
of  the  free  end  of  the  rod.  Crank-pins  are  sometimes 
sprung  from  water  in  the  cylinder. 


CAUSES   OF   KNOCKS  23 

Cases  have  been  found  where,  due  to  mistake  in 
workmanship,  the  crosshead  pin  has  not  been  placed 
perpendicularly  to  the  piston-rod.  This  condition  will 
naturally  result  in  a  tendency  to  side-knock  at  the 
crosshead  pin.  To  ascertain  if  the  crosshead  pin  is 
perpendicular  to  the  piston-rod,  disconnect  the  con- 
necting-rod at  the  crank  and  key  the  crosshead  brasses 
tight,  noting  the  position  of  the  free  end  of  the  rod. 
Then  disconnect  the  rod  at  the  crosshead  and  connect 
it  upside  down  (speaking  of  a  horizontal  engine),  and 
again  key  tightly.  If  the  free  end  of  the  rod  retains 
its  first  position,  the  crosshead  pin  is  true  in  this 
respect. 

Knocks  in  the  crank  and  crosshead  pins  of  old  en- 
gines may  be  the  result  of  the  pins  being  worn  out  of 
round,  and  consequently  they  cannot  be  keyed  up 
properly.  If  this  is  the  case  they  should  be  trued  up 
or  renewed. 

Connecting-rod  brasses  have  a  habit  of  closing  up 
and  gripping  the  pin,  on  account  of  becoming  hot. 
This  will  leave  the  brasses  fitting  the  end  of  the  rod  or 
strap  loosely  and  is  often  the  source  of  knocks.  Fig.  9 
shows  brasses  which  have  been  distorted  from  heating. 
The  manner  in  which  brasses  tend  to  close  up  is  as 
follows:  When  the  surface  of  the  brass  next  to  the 
pin  becomes  hot  suddenly,  the  brass  tries  to  open  as 
the  result  of  expansion  being  greatest  on  the  inside. 
The  rigid  strap  or  rod  prevents  any  movement,  and  the 
metal  is  given  a  permanent  set,  then  when  the  brass 
cools  off  the  ends  come  together.  Ten-inch  brasses 
have  been  known  to  close  up  a  quarter  of  an  inch 


KNOCKS  AND   KINKS 


from  getting  hot  suddenly.  After  the  brasses  have 
run  hot  it  is  usually  necessary  to  relieve  them  on  the 
sides  where  they  hug  the  pin,  and  this  leaves  them 
more  or  less  free  to  rock  in  the  end  of  the  connect- 
ing-rod, causing  knocks.  The  brasses  can  be  filed  or 
machined  square  and  true  on  the  outside  and  heavy 
liners  inserted  to  make  them  fit  the  rod  tightly. 

It  should  be  remembered  that  as  one  keys  up  a 
connecting-rod,  the  center  of  the  pin  is  being  shifted 
slightly  with  respect  to  the  rod.  One  brass  remains 


FIG.    9 

stationary  while  the  other  is  moved  toward  it  by  the 
wedge  or  key.  When  both  wedges  are  placed  between 
the  two  pins,  keying  up  tends  to  make  the  rod  longer 
between  these  parts.  When  one  wedge  is  inside  of  the 
pin  and  another  outside,  the  length  would  remain 
constant  provided  the  wear  was  the  same  on  both 
pins.  But  the  greater  wear  always  occurs  at  the 
crank-pin,  due  to  the  greater  motion  at  this  point. 
It  will  therefore  be  seen  that  keying  up  the  connecting- 
rod  will  slightly  change  the  clearance  in  the  cylinder, 
and  that  ultimately  the  piston  might  knock  the  cylin- 
der-head. 


CAUSES   OF   KNOCKS  25 

It  is  not  usual  to  provide  any  means  for  taking  up 
the  wear  of  bottom  bearings  in  vertical  engines. 
Therefore  as  these  bearings  wear  down  the  clearance 
in  the  bottom  of  the  cylinder  is  reduced.  Besides  the 
possibility  of  the  piston  striking  the  head  from  these 
causes,  it  should  be  observed  that  changing  the  clear- 
ance volume  in  the  cylinder  has  much  the  same  effect 
as  changing  the  lead  and  compression.  Increasing  the 
clearance  will  correspond  to  reducing  lead  and  com- 
pression, and  vice  versa.  It  is  therefore  highly  desirable 
to  have  the  clearance  in  the  cylinder  equally  divided 
at  all  times,  since  much  change  in  clearance  will  tend 
to  cause  knocks  from  what  will  then  correspond  to 
improper  valve  adjustment. 

To  DETERMINE  LOCATION  OF  THE  PISTON 

Figure  10  shows  a  simple  and  reliable  method  of 
determining  at  any  time  the  exact  location  of  the 
piston  in  the  cylinder.  Make  a  clear  mark  all  around 
the  piston-rod  at  some  point  near  the  crosshead. 
When  the  crosshead  is  disconnected  from  the  crank, 
pull  the  piston  forward  until  it  strikes  the  crank-end 
cylinder-head.  Place  a  square  even  with  the  mark  on 
the  rod  and  transfer  to  the  slide  at  A;  then  move  the 
piston  back  until  it  strikes  the  back  head,  measuring 
the  distance  it  moves.  By  subtracting  the  length 
of  the  stroke  you  have  the  total  clearance  in  the 
cylinder.  Measure  this  distance  back  from  A  and 
mark  at  B,  then  midway  between  these  put  a  third 
mark  C.  When  the  engine  is  on  the  head  center,  a 


26 


KNOCKS   AND    KINKS 


square  placed  at  the  mark  on  the  rod  should  fall  on 
the  middle  mark;  if  it  does  not,  the  exact  amount 
which  the  clearance  is  out  is  shown  by  the  discrepancy. 
If  excessive  clearance  is  left  between  the  cranks  and 
bearings,  allowing  lateral  movement  of  the  shaft,  a 
periodic  surging  is  often  set  up,  causing  the  cranks  or 


FIG.    10 


collars  to  knock  against  the  cheeks  of  the  bearings. 
This  will  be  instantly  detected  by  the  wobbly  appear- 
ance of  the  rim  of  the  fly-wheel. 

When  the  fly-wheel  is  loose  on  the  shaft,  a  knock 
will  be  produced  at  the  key.  This  will  usually  occur 
just  after  the  engine  has  passed  the  center.  Many 
wheels  are  built  in  halves  and  the  hub  clamped  onto 
the  shaft  by  bolts.  In  wheels  of  any  considerable  size 
and  weight  it  is  very  difficult  to  get  these  bolts  tight 
enough  to  prevent  slight  movement  between  the  wheel 
and  shaft,  and  the  surer  way  is  to  shrink  the  bolts  in 
the  hub  a  suitable  amount.  In  built-up  wheels  a 


CAUSES   OF   KNOCKS  27 

squeaking  sound  is  often  caused  by  slight  movement 
in  some  of  the  joints.  This  may  sometimes  be  removed 
by  thoroughly  tightening  up  all  bolts,  but  even  this 
may  not  overcome  the  trouble.  There  is  absolutely  no 
danger  from  this  creaking  noise,  but  it  is  very  annoying, 
and  it  is  invariably  the  subject  of  comment  by  all  who 
come  near  the  engine.  When  all  other  methods  fail, 
it  can  usually  be  stopped  by  applying  a  little  oil  about 
the  joints  now  and  then.  An  erector's  trick  is  to 
lightly  coat  all  faces  of  parts  that  go  together  with 
graphite.  This  may  not  improve  the  job  mechani- 
cally, but  the  wheel  won't  squeak. 


IV 


CYLINDER  NOISES 

IN  some  engines  there  will  be  noticed  a  slight  slapping 
or  clicking  noise  at  each  end  of  the  stroke.     Usually 


FIG.    II 


this  noise  is  not  loud  enough  to  indicate  serious  de- 
rangement, but  it  is  very  annoying,  and  in  many  cases 

28 


CYLINDER   NOISES 


29 


mystifying,  baffling  attempts  to  locate  it.  An  erector 
of  analytical  mind  offers  the  following  reasonable 
solution : 

In  such  cases  it  will  usually  be  found  that  the  length 
of  the  counterbore,  or  its  depth  from  the  cylinder  face, 
is  such  that  the  piston  packing  ring  wipes  over  the 
edge  of  the  counterbore  a  considerable  distance,  in 
sorpe  cases  as  much  as  half  the  width  of  the  ring. 


FIG.    12 


This  serves  to  prevent  the  ring  from  wearing  a  shoulder 
in  the  cylinder,  but  leads  to  the  condition  shown  in 
Fig.  1 1 .  Steam  is  admitted  before  the  end  of  the 
stroke,  and  when  the  piston  reaches  the  dead  center, 
a  large  portion  of  the  ring  surface  projects  over  the 
counterbore  and  is  exposed  to  the  steam  pressure,  as 
shown  by  the  arrows  of  Fig.  1 1 .  As  the  ring,  whether 
a  snap  ring  or  a  spring-adjusted  one,  is  not  held  out- 
ward with  any  great  force,  it  is  instantly  collapsed  into 
its  groove  by  this  steam  pressure,  with  a  snap  or  click, 
producing  the  aforesaid  noise.  The  obvious  remedy  is 
to  modify  the  piston  to  permit  the  use  of  a  narrower 


30  KNOCKS   AND    KINKS  . 

ring  which  shall  wipe  just  flush  with  the  edge  of  the 
counterbore,  as  in  Fig.  12,  thus  exposing  none,  or  very 
little,  of  its  surface  to  the  steam  pressure.  Even  should 
a  slight  shoulder  be  worn,  it  is  easily  removed  by  a 
sharp  scraper,  with  much  less  annoyance  than  a  con- 
stant noise  in  the  cylinder. 

Another  similar  noise  is  sometimes  caused  by  the 
imperfect  fit  of  the  packing  ring  in  its  groove. 
The  ring,  as  originally  made,  may  be  narrower  than 
the  groove,  or  its  edges  may  wear  by  long  use  until  it 
is  quite  loose  in  the  groove.  Then  at  each  end  of  the 
stroke,  from  the  reversal  of  motion  and  from  the  steam 
pressure,  the  ring  will  jump  or  slip  over  to  the  other 
edge  of  its  groove  with  a  sharp  "click,"  causing  a  most 
distressing  noise.  The  cure  is,  of  course,  a  new  ring 
made  wide  enough  to  fit  snugly  into  the  groove. 


READY  DETECTION  AND  REMEDY 

WEBSTER  defines  a  knock  as  "a  blow,  a  stroke/'  and 
a  thump  as  "the  sound  made  by  the  fall  of  a  heavy 
body,  as  by  the  blow  of  a  hammer/'  So,  the  operating 
engineer  often  hears  the  "thump"  of  some  part  of  his 
engine,  which  tells  him  that  some  of  the  working  parts 
are  "knocking,"  and  in  due  time  he  will  find  other 
evidence  of  the  same  trouble  in  heated  parts  as  well. 
In  event  of  an  engine  being  already  in  operation,  and, 
possibly,  time  in  which  to  make  inspection  being  very 
limited,  it  is  desirable  to  be  familiar  with  the  very  first 
indications  of  trouble,  and  then,  if  necessary,  prove 
the  evidence  with  tests. 

Knocking,  with  the  consequent  heating  of  the  pins 
or  journals  (or  the  trouble  may  be  in  the  cylinder),  is 
caused  by  loose  adjustment,  a  loosened  bolt  or  nut,  in 
which  case  the  remedy  is  easy  of  attainment ;  or  some 
of  the  parts  of  the  engine  are  out  of  alinement,  which 
is  a  more  serious  matter.  Knocks  may  occur  iff  almost 
any  of  the  working  parts  of  the  engine.  The  most 
prolific  source,  and  the  first  to  consider,  is  the  crank- 
pin,  and  the  troubles  in  the  cylinder  come  second. 
After  this  the  probabilities  of  trouble  from  knocking 
are  about  evenly  divided  among  the  other  engine  parts, 

31 


32  KNOCKS   AND    KINKS 

not  neglecting  the  arm  of  a  fly-wheel,  as  will  be  shown 
by  the  citation  of  two  instances  in  Chapter  VII. 

KNOCKING  OF  THE  CRANK-PIN 

Trouble  with  the  crank-pin  knocking  may  be  caused 
by  a  variety  of  conditions  and  will  be  taken  up  in 
detail.  First  we  will  consider  the  indications  of  this 
trouble  as  they  can  be  observed  with  all  the  connections 
made  up.  Assuming  that  the  boxes  are  properly  keyed 
or  adjusted,  and  everything  is  in  line,  the  appearance 
should  be  as  shown  in  Fig.  13,  which  is  a  plan  view  of 
the  crank-disk  and  adjacent  shaft,  with  the  crank-pin 
connections  shown  at  each  end  of  the  stroke. 

Referring  to  this  illustration,  first  get  the  relative 
positions  and  names  of  the  parts  and  lines  in  mind. 
These  latter  will  be  the  same  in  the  succeeding  similar 
figures. 

The  line  A-B  is  the  center  line  of  the  cylinder,  guides 
and  crank-pin;  M-N  is  the  center  line  of  the  crank- 
shaft at  right  angles  to  A-B;  D  is  a  portion  of  the 
crank-shaft;  E  is  the  crank-disk,  or  in  many  cases  a 
crank-arm  only;  F  F  is  the  stub  end  of  the  connecting- 
rod;  GG  is  the  crank-pin  washer  bolted  on,  or  a  solid 
part  of  the  pin,  as  shown;  /  /  are  the  crank-pin  journal 
boxes ;  K  K  is  the  boss  on  the  crank-disk  or  arm  through 
which  the  pin  projects;  L  L  is  the  crank-pin  itself, 
showing  through  the  spaces  at  the  end  of  the  journal 
boxes.  The  crank-pin  at  the  head-end  center  of  its 
travel  is  indicated  by  //,  and  at  the  crank  end  by  C. 
A  few  turns  of  the  crank  will  allow  the  journal  boxes 


READY   DETECTION   AND   REMEDY 


33 


to  find  their  own  center  of  location,  and  if  the  shaft  is 
in  proper  alinement  with  the  center  line  of  the  cylinder 
and  the  crank-pin  is  in  proper  alinement  with  the 
shaft,  the  appearance  and  position  of  the  parts  will  be 
substantially  as  shown,  with  an  even  space  all  around 


G    , 


FIG.    13 

the  circumference  of  the  crank-pin  washer  and  the 
journal  boxes,  and  the  crank-pin  boss,  and  the  journal 
boxes,  at  all  positions  of  the  crank  in  its  travel. 

When  a  knock  is  located  in  the  crank-pin,  one  of 
several  conditions  may  exist.  In  the  case  of  the 
crank-shaft  being  out  of  square  with  the  center  line  of 
the  cylinder,  the  condition  may  be  as  shown  in  Fig.  14. 


34 


KNOCKS   AND    KINKS 


The  evidence  of  this  condition  may  appear  as  follows: 
The  line  A-B  being  the  center  line  of  the  engine,  and 
M-N  the  true  center  line  of  the  crank-shaft,  we  find 
the  crank-shaft  so  located  that  its  existing  center  is 
along  the  line  O-P.  This  condition  will  act  on  the 


FIG.    14 

crank-pin  as  follows:  The  shaft  being  on  the  center  line 
O-P,  it  will  pivot  at  the  point  G  back  of  the  crank-disk 
and  throw  the  crank-pin  out  of  line. 

When  the  crank  is  at  H,  the  center  of  the  pin  will 
be  shifted  and  the  journal  boxes  not  having  enough 
clearance  on  the  sides,  the  center  line  of  the  connecting- 
rod  will  be  so  changed  as  to  be  in  a  direction  indicated 


READY   DETECTION   AND    REMEDY  35 

by  the  line  a-a.  When  the  crank  is  turned  to  the  point 
C,  the  center  line  of  the  connecting-rod  is  changed  to 
the  other  side  of  the  line  A-B  in  the  direction  indi-' 
cated  by  the  line  b-b.  Owing  to  the  fact  that  in  both 
positions  shown  in  Fig.  14,  e-e  and  /-/  are  at  a  greater 
angle  from  the  line  A-B  than  the  lines  a-a  and  b-b,  the 
openings  to  be  observed  between  the  journal  boxes 
and  the  washer  at  one  side,  and  the  boss  at  the  other, 
will  be  at  the  points  XXXX  in  both  positions. 

In  Fig.  15,  the  lines  A-B  and  M-N  being  the  same 
as  previously  shown,  we  find  the  existing  center  of  the 
shaft  along  the  line  0-P  opposite  its  position  in  Fig.  14. 
When  the  crank  is  at  H,  the  center  line  of  the  connect- 
ing-rod will  be  along  the  line  c-c,  and  when  at  C,  the 
same  line  will  be  d-d.  The  openings  to  be  observed 
will  be  at  the  points  XXXX. 

With  the  conditions  as  shown  in  Figs.  14  and  15, 
the  openings  will  be  noticeable  at  the  points  indicated. 
There  will  be  no  noticeable  opening  when  the  crank  is 
on  the  quarter  positions.  At  the  two  quarters,  the 
lines  a-a,  b-b,  c-c  and  d-d,  shown  in  Figs.  14  and  15, 
will  be  almost  even  \vith  and  parallel  to  the  line  A-B, 
although  the  pin  center  lines  e-e  and  /-/  in  Fig.  14  will 
be  at  the  same  angle,  so  that  when  the  positions  are 
as  at  Fig.  14,  and  the  crank  is  on  either  quarter,  the 
openings  XXXX  will  be  in  the  same  relative  positions. 

In  Fig.  15,  when  the  crank  is  on  the  quarters,  the 
openings  will  be  (for  the  same  reason)  on  the  corners 
shown  in  this  figure.  If  time  allows,  a  good  way  to 
verify  the  conditions  as  shown  is  to  disconnect  the 
connecting-rod  from  the  crank-pin  and  swing  it  free 


KNOCKS   AND    KINKS 


over  the  pin  to  the  positions  H  and  C.  When  the  pin 
is  at  f/,  Fig.  14,  the  crank-pin  boxes  would  swing  over 
the  outside  end  of  the  pin  away  from  the  disk;  and 


1JH 


H 


FIG.    15 

when  at  C,  it  would  swing  in  over  the  disk.     In  Fig.  1 5, 
the  conditions  would  be  reversed. 

Figures  16  and  17  are  elevation  sketches  of  the  same 
crank;  A-B  is  the  center  line  of  the  crank  travel  at 
right  angles  to  the  line  M-N,  the  true  center  of  the 
shaft,  horizontal  and  level;  T-Q  being  the  position  at 
the  top  quarter  of  the  stroke  and  B-Q  the  position  at 


READY   DETECTION   AND   REMEDY 


37 


the  bottom.  In  Fig.  16,  the  line  0-P  is  the  existing 
center  of  the  shaft  where  the  outer  end  is  lower  than 
the  crank  end.  With  this  condition  of  the  shaft,  the 
greatest  openings  between  the  journal  box  flanges  and 
the  adjacent  surfaces,  will  be  at  the  points  XX;  and 
in  Fig.  17,  with  the  line  0-P  showing  the  outer  end  of 
the  shaft  higher  than  the  crank  end,  the  greatest 
openings  will  be  at  X  X.  If  the  crank  shaft  is  out  of 


gr 


FIG.    16 

level  as  in  Figs.  16  and  17,  the  least  amount  of 
unequal  space  noticeable  will  be  when  the  crank  has 
reached  the  two  centers. 

For  example,  if  in  Fig.  14,  the  clearance  spoken  of 
was  great  enough  so  that  the  center  line  of  the  con- 
necting-rod was  not  changed  from  the  line  A-B,  then 
there  would  be  a  clearance  all  around  between  the 
edge  of  the  crank-pin  boxes  and  the  crank-pin  boss  at 
H,  but  greatest  at  the  point  X  on  that  side;  and  with 
the  brass  and  cap  touching  at  the  point  opposite,  there 
would  be  an  opening  at  the  other  point  X  as  shown. 

With  the  crank  at  the  point  C  under  the  same  con- 


KNOCKS   AND   KINKS 


ditions  of  clearance,  the  opening  all  around  would  be 
between  the  crank-pin  cap  and  journal  boxes,  being 
greatest  at  the  point  X;  and  touching  the  crank-pin 
boss  opposite  the  last  point  named,  there  would  be  an 
opening  at  the  point  X  on  that  side.  In  Fig.  15,  with 
enough  clearance  of  journal  brasses,  the  opening  all 
around  with  the  crank  at  H  would  be  between  the 
washer  or  cap  and  the  boxes,  and  when  the  crank  is 

TO! 


M 


BOj 


FIG.    17 

at  C,  the  openings  would  be  between  the  boss  and 
boxes,  or  exactly  opposite  to  conditions  in  Fig.  14. 
Figs.  14  and  15  show  the  appearance  of  the  openings 
when  there  is  not  enough  clearance  between  the  ends 
of  the  boxes,  and  the  center  line  of  the  connecting-rod 
is  changed  from  that  of  the  cylinder  line  A-B,  and  this 
would  apply  as  well  to  the  appearance  of  the  openings 
when  the  shaft  was  located  as  in  Figs.  i6.and  17. 

REMEDIES  FOR  KNOCKING  CRANK-PIN 

When  the  trouble  is  such  as  depicted  in  Figs.  14  and 
15,  it  is  a  matter  of  swinging  the  outer  end  of  the  shaft 


READY   DETECTION   AND   REMEDY  39 

Around  so  that  the  line  0-P  will  coincide  with  the  line 
M-N,  as  in  Fig.  13.  In  order  to  do  this,  the  outboard 
bearing  must  be  moved  in  a  horizontal  line  and  parallel 
to  the  line  A-B,  in  a  direction  towards  the  cylinder  in 
Fig.  14  and  away  from  it  in  Fig.  15. 

Some  engines  have  an  outboard  bearing  similar  to 
Fig.  1 8,  where  the  bearing  cap  comes  down  on  two 
separate  half  shells  b  b,  adjustment  being  made  by  the 
bolts  c  c.  These  bolts  are  secured  by  lock-nuts.  The 


FIG.    18 

shells  have  room  in  the  frame  for  lateral  movement,  as 
shown  by  the  spaces  -a  a  on  each  side. 

To  adjust  this  end  of  the  shaft,  first  loosen  up  on 
the  holding-down  bolts  of  the  cap,  slacken  off  the  lock- 
nuts  on  bolts  c  c,  and  slacken  off  the  bolt  c  on  the  side 
toward  the  direction  you  wish  to  bring  the  shaft  center. 
Then  shove  the  shell  over  by  setting  up  on  the  opposite 
bolt.  After  the  desired  position  is  secured,  set  up  on 
the  bolt  c  which  you  first  slacked  off,  until  the  lower 
shell  is  fast  between  the  adjusting  bolts,  and  set  up 
and  secure  the  lock-nuts  and  the  holding-down  bolts. 


40  KNOCKS  AND   KINKS 

On  this  style  of  bearing,  the  liner  adjustment  is  made 
between  the  two  shells  at  the  edges  and  in  the  spaces  d, 
leaving  the  spaces  e  e  clear  of  liners. 

Figure  18  is  simply  a  representation  of  a  type  of 
bearing  which  has  many  variations  in  design,  but  all 
give  opportunity  for  lateral  adjustment.  Some  bear- 
ing blocks  are  without  this  adjustment,  as  shown  in 
Fig.  19.  In  this  case  if  the  journal  sets  on  a  sub-base, 
it  may  be  possible  to  chip  out  the  bolt  holes  //  suffi- 


FIG. 


ciently  to  get  the  required  adjustment.  If  not,  a 
change  in  the  position  of  the  sub-base  will  be  necessary. 
This  may  require  considerable  labor,  for  it  may  be 
necessary  to  cut  away  the  joint  between  the  sub-base 
and  foundation  and  make  a  new  joint,  with  the  possible 
changing  of  the  foundation  bolts.  Another  thing  to 
look  out  for,  when  the  engine  is  direct-connected  to  a 
generator,  is  to  see  that  the  field  or  armature  frame  is 
set  (after  any  changes  in  position  of  the  shaft  are 
made),  so  that  the  space  between  the  stationary  and 
revolving  pieces  is  equal  all  around. 


OF  THE 

UNIVERSITY 

OF 


READY   DETECTION   AND   REMEDY 


Main  bearings  have  been  seen  such  as  shown  in 
Fig.  20,  with  quarter-boxes  c  and  d,  and  a  wedge 
adjustment  b  in  front,  but  only  the  quarter-box  d  in 
the  back  or  even  no  quarter-box  at  all,  with  a  complete 
bearing  from  point  e  to  point  /  on  the  circumference. 
On  this  style  of  bearing,  when  excessive  wear  has 
taken  place  and  all  the  adjustment  has  been  on  one 


FIG.    2O 

side,  a  condition  of  affairs  as  shown  in  Fig.  14  may 
have  been  brought  about.  If  there  is  a  quarter-box  d 
in  the  main  bearing,  a  liner  behind  it  will  cure  the 
trouble;  if  there  is  no  quarter-box  here,  the  bearing 
will  need  re-babbitting.  When  trouble  is  met  with 
such  as  depicted  in  Figs.  16  and  17,  it  is  a  question  of 
raising  or  lowering  the  outboard  bearing  so  that  the 
shaft  will  be  level  and  the  line  0-P  will  conform  to  the 
line  M-N. 


42  KNOCKS  AND   KINKS 

If  we  have  an  outboard  bearing  on  a  sub-base  as  in 
Fig.  19,  the  matter  of  lining  the  bearing  in  a  case  like 
Fig.  1 6  is  an  easy  one.  Take  thin  steel  wedges,  say 
2  inches  wide,  with  a  taper  of  not  over  J  inch  to  the 
foot,  and  drive  between  the  bearing  frame  and  sub-base 
(first  loosening  up  on  the  holding-down  bolts),  until 
there  is  enough  space  to  insert  liners  at  AAA.  Be 
careful  to  insert  the  same  thickness  of  liner  at  each 
place.  Before  inserting  a  liner,  examine  it  to  see  that 
all  burs  are  removed  on  the  edges  and  surfaces  so  that 
its  entire  surface  will  have  a  bearing.  After  a  suffi- 
cient number  have  been  placed  to  bring  the  shaft  level, 
set  up  on  the  holding-down  bolts  in  the  sub-base.  On 
very  heavy  engines,  a  hydraulic  jack  may  be  needed 
to  lift  the  shaft  in  making  these  changes. 

Where  there  is  no  opportunity  to  line  up  the  outboard 
bearing,  either  the  journal  must  be  re-babbitted  or  the 
whole  frame  must  be  wedged  up  from  the  foundation 
and  new  grouting  put  in.  When  conditions  are  as 
shown  in  Fig.  17,  the  trouble  is  most  likely  in  the  main 
bearing.  In  this  case  the  line  O-P  would  practically 
be  at  the  proper  angle  but  the  point  of  its  divergence 
from  the  line  M-N  would  be  near  the  outboard  bearing. 
If  the^ bottom  part  of  the  main  bearing  is  a  shell  sepa- 
sate  from  the  frame,  liners  can  be  placed  underneath 
to  raise  it.  If  there  is  no  bottom  shell,  it  will  be  a 
case  of  re-babbitting  the  bearing. 


READY   DETECTION   AND   REMEDY 


CRANK-PIN  OUT  OF  LINE  WITH  DISK 


43 


Referring  to  Fig.  21  we  have  four  different  positions 
of  the  crank-pin  in  one  revolution;  at  H  the  head  end, 
C  the  crank  end,  T-Q  or  top  quarter,  and  B-Q,  the 
bottom  quarter.  In  this  case  the  shaft  is  at  right 


A-N 


FIG.    21 


44  KNOCKS   AND   KINKS 

angles  with  the  line  A-B,  but  the  crank-pin  is  out  of 
square  with  the  shaft  center  line  M-N;  and  in  the  illus- 
tration it  will  be  noted  that  at  all  positions  of  the 
crank,  the  angle  at  which  the  crank-pin  sets  is  inclined 
toward  the  line  M-N.  With  an  engine  knocking  from 
this  condition  of  affairs  the  crank-pin  journal  can  very 
likely  keep  its  true  center,  but  it  will  always  bear 
against  the  outside  cap  or  washer.  In  turning  the 
engine  around  by  hand  the  appearance  will  be  as 
shown,  with  the  exception  of  the  bottom  quarter, 
where  the  weight  of  the  rod  will  shift  the  journal  to 
the  inside.  If  the  pin  were  inclined  at  an  angle  oppo- 
site to  the  one  shown,  away  from  the  line  M-N,  the 
positions  above  would  be  reversed.  The  greatest  open- 
ing to  be  observed  in  this  case  are  between  the  journal 
boxes  and  adjacent  surfaces  would  be  at  XXXX. 

This  condition  of  crank-pin  may  be  caused  by  being 
warped  out  of  place  in  cooling  after  being  shrunk  in. 
In  this  event  it  would  most  likely  be  a  matter  of 
forcing  the  crank-arm  or  disk  from  the  shaft  and 
reboring  the  crank-pin  eye.  The  work  might  be  done 
with  a  boring-bar  outfit,  properly  set.  In  any  event 
a  new  pin  would  be  required. 

LOOSE  CRANK-PIN 

On  most  side-crank  engines  two  ways  of  securing 
the  crank-pin  are  used.  Fig.  22  shows  the  pin  either 
forced  through  the  eye  hydraulically,  or  shrunk  in  until 
it  brings  up  on  the  shoulder  a  and  is  riveted  over  on 
the  end  b.  In  Fig.  23,  the  pin  is  forced  through  the 
eye  as  in  Fig.  22  and  is  secured  in  place  by  a  nut  a. 


READY   DETECTION   AND   REMEDY 


45 


Sometimes  the  pin  loosens  up  in  the  eye  and  causes  a 
knock.     It  can  be  found  by  close  inspection  at  the 


FIG.    22 


back  of  the  disk  or  by  stripping  the  pin  of  its  brasses. 
If  this  condition  has  long  existed,  the  eye  is  not  true 
and  needs  reboring  before  a  new  pin  is  inserted. 


f 


FIG.    23 


KNOCKS   AND   KINKS 

FLAT  CRANK-PIN 


More  frequent  than  a  loose  pin,  is  a  flat  one,  as  shown 
in  Fig.  24  at  a.  The  reason  the  pin  wears  flat  here  is 
that  the  greatest  pressure  is  just  after  it  has  left  the 


FIG.    24 


centers  and  up  to  and  arriving  at  the  quarters.  This 
does  not  allow  proper  adjustment  of  the  boxes  and 
causes  knocking.  A  crank-pin  6  inches  in  diameter 


FIG.    25 

has  been  known  to  wear  flat  J  of  an  inch.  It  is 
easily  discernible  when  the  pin  is  stripped  and  the 
only  solution  of  the  trouble  is  a  new  pin,  or  in  an 


READY   DETECTION   AND    REMEDY 


47 


emergency,  the  filing  of  the  pin  round,  by  a  mechanic 
who  knows  how  to  do  it. 

In  Figs.  22  and  23  are  shown  crank-pins  with  the 
outside  ends  c  c  turned  solid  with  the  rest  of  the  pin. 


FIG.    26 


This  style  of  crank-pin  is  generally  used  with  the  strap, 
gib-and-key  connection  shown  in  Fig.  25.  Crank-pins 
with  a  detachable  cap  at  c  are  used  with  connections 
such  as  shown  in  Fig.  26. 


KNOCKING  AT  THE  CROSSHEAD 

The  crank-pin  being  out  of  position  as  shown  in 
Figs.  14,  15  and  21  and  in  a  condition  opposite  to  that 


FIG.    27 


48 


KNOCKS   AND    KINKS 


spoken  of  in  Fig.  21,  will  have  an  effect  on  the  cross- 
head,  causing  it  to  knock  sidewise,  especially  if  it  has 
flat  or  round  shoes. 

Trouble  with  the  crosshead  pin  being  out  of  line  is 
not  very  frequent,  but  it  sometimes  wears  flat  on  the 


FIG.    28 

two  sides  a  a,  Fig.  27.  The  pin  should  be  taken  out 
and  turned  true  and  the  boxes  turned  to  suit  the  new 
pin,  then  it  should  be  flattened  on  the  sides  a  a,  as  in 
Fig.  28.  This  will  allow  of  considerable  wear  and 
adjustment  without  renewal  of  the  pin. 

CYLINDER  OUT  OF  LINE 

Figure  29  is  a  sectional  view  of  an  engine  cylinder 
and  crosshead  guides  where  the  line  A-B  represents 
the  center  line;  C  is  the  crosshead,  D  the  piston  in  the 
crank  end  of  the  cylinder  and  E  the  piston  in  the  head 
end,  F  being  the  piston-rod.  Owing  to  the  fact  that 
most  engine  cylinders  are  secured  to  the  frame  in  some 
style  similar  to  that  shown,  there  is  not  much  danger 
of  the  cylinder  being  out  of  line  at  the  point  where  it 
joins  the  frame.  The  frame  face  and  flange  around  it 


READY    DETECTION   AND   REMEDY 


49 


at  a  are  bored  and  faced  at  the  same  setting  with  the 
guides.  But  on  account  of  the  human  element  in 
engine  building  and  operation,  there  may  be  a  setting 


FIG.    29 


of  the  cylinder  which  will  let  the  head  and  rest  too 
high  along  the  line  G-H,  or  too  low  in  the  direction  of 
the  line  I-H,  diverging  either  way  from  the  line  A-B. 


CENTERING  THE  PISTON-ROD 

Sometimes  the  piston  is  low  from  wear  in  the  cylinder. 
Again,  the  piston  and  cylinder  may  be  all  right  and  the 
crosshead  be  either  high  or  low.  An  inspection  of  the 
piston-rod  as  it  works  through  the  stuffing-box  gland 
while  running,  will  tell  if  anything  is  wrong  here.  To 
find  where  the  trouble  lies,  first  take  off  the  front 
cylinder-head,  turn  the  engine  until  the  piston  is  at  E, 
and  with  a  pair  of  calipers  b,  proceed  to  find  out  if  the 
piston  is  central  in  the  cylinder.  To  do  this,  place 
the  divider  point  in  the  piston  center  with  the  caliper 
leg  swinging  around  the  counterbore.  The  latter 
should  always  be  worked  from,  as  the  cylinder  may 
be  worn  as  well  as  the  piston  itself. 

After  centering  the  piston  in  the  cylinder,  turn  the 


50  KNOCKS  AND   KINKS 

engine  over  so  that  the  crosshead  shoe  will  clear  the 
head  end  of  the  guide,  permitting  a  pair  of  inside 
calipers  to  be  used,  one  leg  resting  on  the  wearing 
surface  of  the  guide  and  the  other  point  just  "feeling" 
the  bottom  of  the  piston-rod  at  c.  Now  turn  the  engine 
until  the  piston  is  at  D  and  the  crosshead  as  shown  at 
the  crank  end  of  the  guide.  Taking  care  that  the 
calipers  have  not  been  changed,  try  the  distance  be- 
tween the  same  guide  and  piston-rod  at  d.  Take  care 
to  note  if  any  shoulder  is  worn  on  the  rod  and  if  so 
try  the  calipers  on  the  rod  inside  the  shoulder  away 
from  the  crosshead.  The  distance  between  the  guide 
and  rod  at  d  should  be  the  same  as  at  c.  Then  with 
the  calipers  still  set  as  at  c,  and  the  crosshead  and 
piston  remaining  on  the  crank  end  of  the  stroke,  again 
try  the  distance  between  the  guide  and  rod  at  c.  In 
measuring  with  a  pair  of  calipers,  a  light  pair  should 
be  selected,  and  the  longer  the  legs  the  better.  In 
using  them,  care  should  be  taken  to  have  the  two 
points  come  into  contact  exactly  opposite  each  other 
and  that  the  "feeling"  point  is  not  forced  into  contact, 
but  just  "  feels  "  the  surface  to  which  you  are  measuring. 
This  is  an  art  acquired  only  by  practice. 

After  we  have  come  the  second  time  to  point  c  on 
the  rod  and  find  the  rod  is  lower  than  at  point  d,  one 
of  two  things  is  wrong;  either  the  head  end  of  the 
cylinder  is  high  or  the  crosshead  is  high,  and  if  the 
rod  is  higher  at  c  than  at  d,  the  head  end  of  the  cylinder 
is  low  or  the  crosshead  is  low. 

There  are  so  many  designs  of  engine  parts,  that  a 
detailed  descripti9n  of  every  move  to  make  to  change 


READY   DETECTION   AND    REMEDY  51 

these  conditions  on  even  a  few  of  the  leading  ones 
would  be  too  long  for  the  space  at  hand.  But  assuming 
that  the  engineer  knows  how  to  correct  the  conditions, 
it  is  suggested  at  this  point  that  he  change  the  hight 
of  the  crosshead  while  it  rests  at  the  crank  end  of  the 
guides,  until  by  frequent  trial  of  the  calipers  at  both 
points  mentioned,  -c  and  d,  he  finds  the  rod  exactly 
parallel  with  the  guides.  Then  turn  the  engine  over 
again  until  there  is  just  sufficient  room  left  at  the 
head  end  of  the  guide  to  caliper  the  distance  at  c. 
Very  careful  calipering  will  now  be  necessary  to  detect 
a  difference.  If  the  rod  is  high  now,  the  head  end  of 
the  cylinder  is  high;  if  the  rod  is  low,  the  head  end  of 
the  cylinder  is  low. 

If  the  piston  is  worn  small  on  the  bottom,  as  is  often 
the  case  with  horizontal  engines,  it  must  be  raised. 
Some  pistons  are  made  with  follower  and  bull  rings, 
and  in  this  event  there  is  always  some  way  of  raising 
the  center.  If  the  piston  is  solid  it  can  sometimes  be 
turned  around  half  way,  raising  the  center.  But  in 
many  instances  neither  one  of  these  methods  is  avail- 
able, and  either  a  new  piston  must  be  substituted  or 
the  old  one  turned  off  and  a  new  ring  shrunk  on.  If 
the  cylinder  bore  is  worn  badly  it  must  be  rebored  and 
a  new  piston  of  the  right  size  fitted. 

All  pistons  should  be  so  set  that  at  each  end  of  the 
stroke  the  first  piston-ring  will  pass  over  into  the 
counterbore  as  is  shown  at  e  e,  and  the  crosshead  shoes 
should  go  over  each  end  of  the  guides  as  at  /  /.  Some- 
times they  do  not,  and  wear  shoulders  against  which 
they  bring  up  and  cause  knocking.  A  cylinder  with 


52  KNOCKS   AND   KINKS 

no  counterbore  at  all  has  been  known  and  a  shoulder 
at  each  end  was  inevitable.  Another  instance  coming 
under  observation  was  the  case  of  a  low-pressure  piston 
on  a  vertical  engine  of  large  size  being  a  loose  fit,  and 
the  steam  at  each  stroke  on  one  end  seemed  to  throw 
the  piston  over  so  forcibly  as  to  result  in  a  recess  and 
shoulder  in  the  cylinder,  causing  a  heavy  knock.  These 
defects  can  be  found  by  inspection. 

DETERMINING  CLEARANCE 

While  the  front  head  is  off,  take  the  piston  out  and 
take  the  following  measurements: 

On  the  inside  of  the  cylinder  with  a  stick  or  rule 
long  enough,  take  measurement  i,  Fig.  29,  which  is  the 
distance  from  the  bottom  of  the  cylinder  at  the  back 
head  to  the  front  edge  of  the  cylinder  where  the  flange 
of  the  front  head  rests  when  in  place;  next  take  meas- 
urement 2,  the  thickness  of  the  piston-head,  then 
measurement  3,  the  amount  the  front  head  will  extend 
into  the  cylinder  when  in  place  as  indicated  by  the 
dotted  line.  Also  take  a  fourth  (4)  measurement,  the 
stroke  of  the  engine. 

Add  together  2,  3  and  4  and  subtract  the  sum  from 
measurement  i ;  the  difference  will  be  the  total  clear- 
ance in  the  cylinder,  one-half  of  which  will  equal  the 
mechanical  clearance  gg  for  each  end. 

Now  add  this  clearance  to  measurement  3,  and  re- 
placing the  piston  set  it  up  the  distance  of  this  last 
sum  from  the  edge  of  the  cylinder. 


READY  DETECTION  AND  REMEDY  53 

EXAMPLE 

Measurement  1=45!  inches. 
Measurement  2  =  5  inches. 
Measurement  3  =  4  inches. 
Measurement  4=36  inches. 
451  —  (5  +  4  +  36)  =  }  inch  total  clearance, 
i  -^2  =  f  inch  clearance  in  one  end. 
J  +  4  =  4f  inches   distance  of  piston-head  from   front 
edge  of  cylinder. 

This  is  assuming  that  the  crosshead  and  crank-pin 
are  connected  up  and  on  the  head-end  center.  The 
wear  on  the  connecting-rod  end  connections  also  has 
a  bearing  on  the  clearance  as  the  wear  sets  in.  De- 
pending on  the  amount  of  wear  on  the  inside  brasses, 
the  distance  between  the  crank-  and  crosshead-pins  is 
gradually  reduced. 

With  the  style  of  rod  connections  shown  in  Fig.  24, 
the  wear  is  all  taken  up  toward  the  end  and  the  ten- 
dency of  wear  is  to  lengthen  the  centers,  thus  reducing 
the  piston  clearance,  on  the  head  end  of  the  cylinder. 
When  the  clearance  needs  adjusting  from  this  source, 
place  liners  under  the  inside  brasses  between  them  and 
the  stub  ends  of  the  rod,  in  the  event  of  a  gib-and-key 
connection.  With  the  wedge  adjustment  place  liners 
under  the  outside  brasses.  The  crank-pin  brasses  gen- 
erally wear  the  most  rapidly.  If  the  piston-rod  screws 
into  the  crosshead,  secured  with  a  lock-nut,  the  clear- 
ance can  be  adjusted  here  without  reference  to  the 
connecting-rod  adjustment  unless  the  latter  is  brass- 
bound. 


54  KNOCKS   AND   KINKS 

Where  we  have  a  horizontal  engine  of  considerable 
size  running  over,  the  lower  crosshead  shoe  is  inclined 
to  wear  thin  and  bring  the  crosshead  out  of  line.  If 
this  is  not  watched  a  very  considerable  knock  may 
result.  The  reason  is,  that  with  this  lost  motion,  when 
the  engine  passes  the  center,  the  crosshead  is  lifted 
and  almost  immediately  thrown  down  again. 

Most  knocks  in  the  main  and  outer  bearings  are 
caused  by  loose  adjustment  or  the  shaft  being  out  of 
line  as  shown  in  Figs.  14,  15,  i6and  17. 

LOOSE  FLY-WHEELS 

These  very  often  give  trouble,  causing  a  knock  hard 
to  locate.  The  worst  knock  often  occurs  while  the 
engine  is  running  slowly  without  load  and  when 
the  wheel  turns  over  so  that  the  key  is  at  or  near 
the  point  c,  Fig.  33.  (Chap.  7.) 


VI 

EFFECT  OF  INERTIA  OF 'MOVING  PARTS 

USING  compression  to  absorb  the  -inertia  of  the 
moving  parts  is  to  some  extent  good  practice,  but 
going  to  the  extreme  of  sacrificing  economy  to  the 
smooth  running  of  the  engine  should  be  avoided. 
E.  F.  Williams,  a  designing  engineer,  has  this  to  say 
on  the  matter: 

"The  points  of  admission  and  release  are  generally 
manipulated  by  lap  and  lead  on  both  sides  of  the 
valve,  so  as  to  secure  the  most  power  and  best  economy 
without  particular  regard  to  smoothness  of  running. 
As  to  the  running  effect  of  giving  the  valve  more  or 
less  lead,  that  can  be  better  determined  by  practical 
test  than  by  theory. 

"There  are  general  principles,  however,  which  are 
good  guides  to  proper  running  conditions  when  under- 
stood. 

"The  inertia  of  the  reciprocating  parts  is  a  leading 
factor  in  the  operation  of  any  reciprocating  engine. 
The  science  of  inertia  is  of  more  value  to  the  designer 
of  engines  than  to  the  operator,  as  where  the  engine  is 
once  designed  and  speeded,  inertia  becomes  an  inherent 
fixture  entirely  beyond  the  control  of  the  operating 
engineer.  It  is  of  value,  however,  for  the  latter  to 

55 


56  KNOCKS   AND    KINKS 

understand  the  general  rules  for  the  distribution  of 
inertia,  so  as  to  determine  its  force  at  the  ends  of  the 
stroke  where  the  steam  pressure  must  change  direction. 

"Generally  speaking,  it  should  be  borne  in  mind  that 
while  the  steam  pressures  reverse  at  the  ends  of  the 
stroke,  the  inertia  effect  reverses  near  mid-stroke,  where 
the  connecting-rod  becomes  tangent  to  the  crank- 
circle/' 

It  is  well  known  that  smoothness  of  action  at  the 
reversing  points  depends  (other  things  being  considered 


FIG.    30 

equal),  on  how  gradually  or  violently  the  pressures 
change.  The  most  violent  change  would  be  brought 
about  when  conditions  are  as  shown  in  Fig.  30;  there 
being  no  compression  and  inertia  being  inconsiderable. 

About  the  most  favorable  condition  would  be  where 
the  inertia  about  equaled  the  initial  steam  pressure, 
as  at  a,  Fig.  31,  or  even  as  at  b,  in  the  same  figure. 
The  shaded  diagram  being  the  inertia,  set  over  two 
engine  diagrams  joined  on  counter-pressure  lines. 

Less  favorable  conditions  are  established  where  the 
speed  is  sufficient  to  force  quick  reversals  of  pressure 
on  the  crank-pin,  and  not  sufficient  to  generate  an 


EFFECT   OF   INERTIA   OF   MOVING   PARTS 


57 


inertia  effect  equal  to  the  initial  steam  pressure. 
High-speed  engines,  therefore,  operating  at  pretty  high 
pressures,  require  the  most  skilful  management. 

Take  an  ordinary  example  where  the  inertia  runs  up 
to  say,  one-half  or  three-quarters  of  the  initial  steam 


FIG.   31 

pressure,  as  in  Fig.  32.  When  the  compression  just 
about  reaches  and  does  not  surpass  the  inertia  as  at 
b,  it  has  very  little  effect  on  the  reversing  blow  of  the 
steam  which  is  represented  by  the  sudden  rise  of 
pressure  A  and  B  from  the  inertia  line  to  the  initial 
steam  line. 

If,  on  the  other  hand,  the  compression  exceeds  the 
inertia  even  by  a  little,  as  at  a,  it  has  a  very  quieting 
effect.  It  is  important  in  this  connection  for  the  engi- 


58  KNOCKS   AND   KINKS 

neer  to  know  how  great  the  inertia  effect  is  at  each 
end  of  the  stroke.  In  the  first  place  the  actual  weights 
of  piston,  piston-rod,  crosshead  and  connecting-rod 
must  be  known.  This  information  can  generally  be 
obtained  of  the  manufacturer;  if  not,  the  only  way  is 
to  take  the  parts  out  and  weigh  them.  A  close  approx- 
imation may  then  be  made  as  to  the  mean  of  the 


FIG.   32 

inertia  at  the  two  ends  of  the  stroke,  equaling  the 
centrifugal  force. 

Assume  the  reciprocating  parts  of  an  engine  16  by 
24  inches  in  size  to  weigh  704  pounds,  and  the  engine 
speeded  to  200  revolutions  per  minute.  The  area  of 
the  piston  =  20 1  inches;  704^-201=34  pounds,  the 
weight  of  reciprocating  parts  per  square  inch  of  piston 
area. 

The  centrifugal  force  of  a  body  weighing  704  pounds 


EFFECT   OF   INERTIA,  OF   MOVING   PARTS          59 

revolving  in  a  circle  24  inches  in  diameter  at  the  rate 
of  200  revolutions  per  minute  is 


200*  X  704X2 
5870 


pounds,  nearly,  or 

2O02X  2 

"5870" 


=  ,3.58 


times  the  weight,  nearly. 

As  the  weight  is  in  this  case  3^  pounds  per  square 
inch  of  piston  area,  the  mean  inertia  effect  for  the 
two  ends  of  the  stroke  would  be  3.5X13.58  =  47.03 
pounds  per  square  inch  on  the  piston.  Now,  if  the 
pressure  by  compression  is  carried  up  to,  or  a  little 
above,  this  at  the  end  of  the  stroke,  the  quieting  effect 
will  be  good  on  the  moving  parts;  and  if  this  can  be 
done  without  distortion  of  the  steam  diagram  at  the 
cost  of  economy,  the  result  will  be  most  desirable. 

The  inertia  is  greater  at  the  back  end  than  at  the 
front,  owing  to  the  angularity  of  the  connecting-rod. 

This  latter  is  greater  or  less,  depending  on  the 
proportionate  lengths  of  rod  and  stroke. 

The  effect  of  lead  in  a  general  sense  is  that  when  the 
admission  takes  place  (when  the  clearance  is  small)  at 
or  near  the  end  of  the  stroke,  the  effect  is  more  sudden 
than  if  admitted  when  the  piston  is  some  distance 
back  from  the  end  of  the  stroke,  and  the  effect  is  more 
gradual  when  the  piston  is  receding  than  when  it 
is  advancing  toward  the  cylinder-head.  It  often 
occurs  from  this  cause  that  lead  occasions  thump- 


60  KNOCKS   AND   KINKS 

ing,  while  an  absence  of  lead  is  more  favorable  to 
smooth  reversals. 

The  points  given  here  on  this  phase  are  only  a  few 
of  those  to  be  considered  for  a  full  understanding  of 
the  subject,  but  if  understood  are  a  guide  for  further 
changes  if  necessary. 


VII 

SOME  CURIOUS   KNOCKS 

EARLY  in  Chapter  V  a  case  was  referred  to  of  trouble 
occurring  in  a  fly-wheel  spoke.  Some  years  ago  while 
indicating  the  engines  in  a  street-railway  power  house, 
in  the  vicinity  of  New  York  City,  and  while  slowing 
down  one  of  the  engines  a  hard  pound  was  heard 
which  was  so  loud  that  there  was  some  debate  as  to 
the  advisability  of  starting  up  again.  But  as  every- 
thing in  sight  was  as  it  should  be,  the  engine  was 
started;  at  the  first  revolution  the  pound  began  and 
continued  once  every  revolution,  increasing  in  volume 
as  the  engine  was  speeded  up  until  a  good  speed  was 
reached,  when  the  noise  disappeared.  It  caused  much 
worry  until  it  was  finally  located  in  one  spoke  of  the 
wheel.  The  wheel  was  22  feet  in  diameter  and  built 
up  with  hollow  spokes  fastened  with  bolts  to  the  hub, 
and  at  the  other  end  to  a  segment  of  the  wheel  rim 
somewhat  after  the  style  shown  in  Fig.  33.  On  taking 
off  the  segment  a  piece  of  3-inch  extra-heavy  pipe  b, 
3  or  4  feet  long  was  found  inside  the  spoke.  As  the 
wheel  turned  slowly  the  pipe  would  run  down  the 
arm  at  each  revolution  and  ram  the  rim;  for  some 
reason  it  came  back  to  the  hub  easily,  until  sufficient 
speed  had  been  attained  for  centrifugal  force  to  hold 
it  permanently  out  against  the  rim. 

61 


62 


KNOCKS   AND   KINKS 


Some  one  had  evidently  been  ramming  sand  out  of 
the  spoke,  and  jammed  this  piece  of  pipe  in  there  and 


FIG.  33 

left  it;  or  possibly  the  pipe  was  inserted  for  a  core 
in  the  foundry.  The  engine  had  run  some  ten  years 
without  loosening  the  pipe. 

An  amusing  case  of  offending  fly-wheel  occurred  in 
a  large  power  plant  several  years  ago.  When  a  new 
engine  was  started  up  there  was  a  strange  rumbling 
sound  in  the  vicinity  of  the  wheel,  which  was  sufficient 
to  make  any  one  apprehensive.  A  thorough  examina- 
tion revealed  nothing,  and  the  engineer  representing 
the  engine  builder  laid  the  trouble  to  the  generator. 
After  several  attempts  at  starting,  it  was  discovered 
that  when  the  engine  got  above  a  certain  speed  the 
noise  ceased.  It  was  a  segmental  wheel,  linked  to- 


SOME  CURIOUS   KNOCKS  63 

gether  at  the  rim.  In  order  to  make  a  "stocky" 
looking  wheel,  the  builders  cored  out  the  rim,  making 
a  hole  about  five  inches  square  all  around  the  rim. 
After  the  engine  had  run  for  some 'weeks,  making  the 
noise  when  starting  and  stopping,  and  had  caused 
many  days  and  nights  of  brain  racking,  a  conscience- 
stricken  laborer  confessed  that  he  had  accidentally 


FIG.  34 

dropped  a  large  wrench  into  the  cavity  in  the  rim 
before  the  last  segment  was  put  in  place.  To  remove 
a  segment  would  have  been  expensive,  so  the  method 
of  stopping  the  noise  shown  in  Fig.  34  was  used.  A 
hole  was  drilled  and  tapped  from  the  inner  side  of  the 
rim  into  the  cavity  and  a  long  stud  provided.  By 
turning  the  wheel  the  wrench  was  got  directly  under 
the  hole  and  the  stud  was  screwed  down,  clamping  the 
wrench  firmly.  This  wrench  has  now  traveled  farther 
than  any  other  member  of  its  tribe. 


VIII 


RIGGING   UP  TO  TURN   AND    REFIT   LARGE 

PISTONS  — A  CRANK-PIN  TURNING 

DEVICE  1 

THIS  not  only  is  a  large  job  done  in  a  satisfactory 
manner  in  a  shop  having  small  tools  only,  but  also  it 
shows  how  an  efficient  special  machine  was  built  from 
material  rescued  from  our  old  friend  and  standby,  the 
scrap  heap. 

The  plant  where  the  work  was  done  is  a  large  power 
station  with  eight  compound  engines  having  cylinders 
42  and  86  inches  by  60  inches  stroke;  steam  pressure, 
1 80  pounds;  revolutions  per  minute,  75.  These  en- 
gines were  built  to  develop  4500  horse-power,  but  are 
run  anywhere  up  to  6000  horse-power.  Six  engines  are 
in  commission  at  a  time  while  a  standby  engine  is  kept 
just  turning  over  so  that  at  a  moment's  notice,  in  case 
of  accident,  it  can  be  started  at  full  speed.  The  re- 
maining engine  is  undergoing  any  necessary  over- 
hauling. 

The  pistons  of  the  low-pressure  cylinders  are  86 
inches  diameter  by  15  inches  deep.  Two  inches  from 
each  face  there  is  a  packing-ring  groove  B,  Fig.  36, 
ii  inches  wide.  The  pistons  cost  when  new  $664,  and 

1  Contributed  to  Power  by  Dixie. 
64 


A   CRANK-PIN  TURNING   DEVICE  65 

when  put  in  are  about  0.032  smaller  in  diameter  than 
the  cylinders.  After  a  year  and  a  half  they  are  found 
to  have  worn  approximately  f  inch,  and  if  they  could 
not  be  repaired  would  be  a  total  loss. 

It  was  decided  to  try  cutting  grooves  in  one  of  the 
pistons  and  lining  it  with  babbitt.  This  was  done  and 
gave  such  highly  satisfactory  results  that  as  they 
become  worn  and  can  be  spared  the  other  pistons 
receive  the  same  treatment.  ' 

The  largest  lathe  in  the  repair  shop  is  a  24-inch 
Putnam  with  a  bed  about  10  feet  long.  It  was,  of 
course,  out  of  the  question  to  turn  up  the  86-inch 
pistons  on  this  lathe,  but  it  came  in  for  the  work  on 
the  piston-rods  later  on.  Out  in  the  scrap  heap  was 
a  bent  piston-rod  —  not  very  much  bent,  but  just 
enough  to  put  it  out  of  business  for  the  work  for  which 
it  was  intended. 

This  was  brought  in  and  a  couple  of  journals  turned 
on  it  about  six  feet  apart  and  true  with  the  taper  seat 
for  the  piston.  Two  bearings  were  fitted  to  these 
journals.  Masonry  piers  were  built  18  x  24  inches  and 
high  enough  to  suit  the  job.  To  these  lox  5-inch 
I-beams  were  secured  by  bolts  built  into  the  masonry. 
On  top  of  the  10  x  5-inch  I-beams,  12  x  5-inch  I-beams 
were  bolted,  and  to  these  the  two  bearings  were 
secured,  all  of  which  is  shown  in  the  half-tone,  Fig.  35. 
The  slide  at  the  left,  upon  which  the  tool  slide  is 
mounted,  is  equipped  with  a  carriage  having  screw 
feed,  which  serves  for  longitudinal  feed  for  the  tool. 
The  tool  slide  is  taken  from  the  24-inch  lathe  previously 
referred  to.  '  The  pistons  are  mounted  on  the  end  of 


66  KNOCKS   AND   KINKS 

the  piston-rod  which  forms  the  spindle  of  the  machine, 
and  six  dovetailed  grooves  ij  inches  wide  by  J  inch 
deep  are  turned  in  them,  as  shown  at  A,  Fig.  36. 
This  job  took  eight  hours,  which  is  pretty  quick 
time.  After  grooving,  a  wooden  form  lined  with 
asbestos  board  and  taking  in  about  \  of  the  circum- 
ference is  clamped  to  the  piston  and  the  grooves  are 


FIG. 


poured  with  babbitt.  The  six  segments  of  babbitt  are 
not  allowed  to  abut,  there  being  a  space  of  about  i  to 
j  inch  between  their  ends.  After  all  the  segments  are 
filled  with  babbitt,  the  babbitt  is  pened  into  the  groove, 
the  pening  at  the  same  tiijie  that  it  compresses  the 
metal  spreads  it  so  that  the  segments  creep  toward 
each  other,  making  a  perfectly  tight  joint  at  their 
ends.  After  the  segments  are  all  pened  solid  they  are 
turned  to  size,  the  "whole  job  taking  but  three  days. 
The  first  cylinder  fitted  with  one  of  these  doctored 


A  CRANK-PIX  TURNING   DEVICE 


67 


pistons  has  now  a  fine  glazed  surface  on  it,  and  is  the 
only  one  that  has. 

The  crosshead  shoes  of  these  engines  are  also  babbitt 


FIG.   36 

lined  and  are  turned  to  size  in  the  same  fixture,  but 
between  the  bearings.    The  rig  shown  in  Fig.  37  shows 


FIG.    57 


a  spare  crosshead  secured  to  a  shaft  with  journals  on 
it  which  fit  the  bearings  on  the  turning  rig.  The  large 
gear  on  the  spindle  of  the  turning  rig  is  split  so  that  it- 


68 


KNOCKS   AND    KINKS 


can  be  easily  shifted  from  the  one  job  to  the  other. 
The  tool  slide  is  also  portable,  of  course. 

A  CRANK-PIN  TURNING  RIG 

Figure  38  shows  a  crank-pin  turning  device.     In  this 
rig  A  is  a  rotating  sleeve  journaled  in  the  casting  B, 


FIG.    38 

which  slides  on  the  angle  casting  C,  being  actuated  by 
the  screw  D,  working  in  the  nut  E.  A  worm  F  meshes 
with  worm  teeth  cut  in  the  center  of  the  periphery  of 
A.  The  worm  F  is  driven  through  the  worm  gear  G, 
the  worm  H,  and  the  shaft  /  by  the  pulley  K.  The 
sleeve  A  carries  the  turning  tool  /.  The  sleeve  A  is 
not  shown  in  halves  in  the  illustration,  but  can  be  so 
made.  It  is,  of  course,  understood  that  no  attempt 
has  been  made  to  make  the  drawing  to  scale. 
The  face  X  of  the  angle  casting  C  is  set  true  with 


A  CRANK-PIN  TURNING   DEVICE 


69 


the  crank  web,  and  the  sleeve  A  concentric  with  the 
crark-pin.  The  tool  /  is  set  to  depth  of  cut  and  the 
machine  is  started.  The  feed  is  by  means  of  a  star 
wheel  on  the  end  of  the  screw  D. 

TURNING  LONG  PISTON-RODS  ON  A  SHORT  LATHE 

The  spare  piston-rods  for  these  engines  are  about  two 
feet  longer  than  the  longest  lathe  in  the  shop.  The 
threads  on  either  end  for  the  nuts  and  the  taper  for 


FIG.  39 

the  pistons  have  been  left  a  "little  full."  When  it 
came  to  fitting  a  new  rod,  these  oversizes  were  noticed, 
and  it  was  necessary  to  devise  some  means  for  doing 
the  job  of  turning  them  to  size.  This  is  shown  at 
Fig.  39.  A  is  the  piston-rod,  B  is  a  small  cast-iron 
piece  drilled  for  three  cap  screws.  The  ends  of  the 
rods  are  drilled  and  tapped  so  that  the  piece  B  can  be 
secured  to  it.  The  piece  B  is  caught  in  the  chuck  and 
the  rod  is  supported  in  a  steady  rest  having  wooden 
jaws.  Even  if  the  piece  B  is  not  central  with  the  rod, 
the  chuck  jaws  can  be  easily  set  so  that  the  rod  runs 
true.  This  made  it  possible  to  reduce  the  threads  and 


70  KNOCKS  AND   KINKS 

the  tapers,  instead  of  re-threading  the  nuts,  which 
would,  of  course,  prevent  their  being  interchangeable, 
as  the  threaded  portions  on  the  spare  rods  were  not  all 
exactly  alike. 

A  PISTON-NUT  WRENCH 

Another  useful  tool  is  shown  at  Fig.  40.     It  is  used 
for  tightening  the  piston  nuts  when  in  place  in  the 


FIG.    40 


engine.  The  flange  A  fits,  with  a  little  play,  the 
manhole  in  the  cylinder  cover.  The  piston  is  brought 
to  top  center,  the  wrench  is  put  in  place,  and  the 
flange  A  steadies  it  so  that  there  is  no  danger  of  its 
being  displaced  while  the  wrench  bar  is  turning  it. 


IX 


REPAIRING    A    BADLY    BROKEN    CYLINDER 

A  30  x  72  Corliss  engine  which  had  been  in  service 
twenty-six  years  at  Atlantic  Mills,  Providence,  parted 


and  let  the  piston  knock  the  back  end  of  the  cylinder 
into  the  condition  shown  by  the  photograph  repro- 
duced herewith  (Fig.  41).  To  make  a  new  cylinder 


72  KNOCKS  AND   KINKS 

would  require  a  month  and  this  delay  in  the  depart- 
ment run  by  the  wrecked  engine  would  seriously  em- 
barrass the  whole  plant.  It  was  concluded  that  the 
broken  cylinder  could  be  repaired,  and  that  the  engine 
could  be  put  in  running  order  in  about  two  weeks. 
It  was  sent  to  the  shop  and  fourteen  days  following 
the  accident  it  was  put  to  work  carrying  the  full  load, 
and  has  run  ever  since  without  developing  a  leak. 

The  break,  as  will  be  seen  by  the  photograph,  fol- 
lowed roughly  the  outside  line  of  the  port,  or  at  least 
did  not  extend  inside  of  that  line,  so  that  Mr.  Giles 
decided  that  it  would  be  feasible  to  plane  the  cylinder 
off  along  the  line  a  b  in  the  drawing,  Fig.  42,  retaining 
the  full  port  width.  A  reinforcing  piece  A  was  secured 
to  the  cylinder  with  its  face  nearly  in  line  with  the 
back  edge  of  the  valve  chamber.  As  the  cylinder  wall 
was  not  of  sufficient  thickness  to  bolt  to  endwise, 
wrought-iron  straps,  one  inch  in  thickness  and  22 
inches  wide,  were  secured  to  the  cylinder  by  ij-inch 
tap-bolts.  The  steam-chest  was  planed  off  upon  the 
lines  indicated  by  the  drawing,  and  the  breaks  in  the 
flange  and  continguous  cylinder  wall  squared.  A  pat- 
tern was  made  for  a  piece  to  fit  the  surfaces  thus 
created,  and  the  casting  bolted  to  the  cylinder  and 
reinforcing  pieces  as  shown,  those  holding  longitudi- 
nally being  put  in  first  and  the  surfaces  forced  into 
contact  at  right  angles  thereto  under  heavy  pressure, 
aided  by  blows  with  a  battering-ram  while  being  bolted 
up.  The  joint  was  made  tight  by  running  a  soft 
copper  wire  around  inside  of  the  bolts,  which  were 
heated  to  as  high  a  temperature  as  practicable  before 


REPAIRING   A   BADLY   BROKEN   CYLINDER 


73 


being  set  up,  so  that  in  cooling  they  would  draw  the 
surfaces  tightly  together.  This  wire  terminated  at  c 
and  c,  where  f-inch  holes  were  drilled,  which,  after 
the  wire  had  been  cut  off,  were  plugged  with  brass 


I  „•..«_.:. . ; 

f ; La-'sfc'./ *  lH''H 


REPAIRING   A   BADLY  BROKEN   CYLINDER. 

FIG.    42 


plugs  chilled  before  driving,  so  that  their  expansion 
would  close  the  longitudinal  gap.  It  is  the  worst  case 
we  have  ever  seen,  and  the  owners  of  the  engine  are 
warm  in  their  expression  of  appreciation  of  the  inge- 
nuity, enterprise  and  thoroughness  which  thus  helped 
them  out  of  a  bad  situation. 


X 


REMOVING  A  TIGHT  PISTON-ROD  FROM 
CROSSHEAD 

THE  piston-rod  of  an  18  x  24-inch  slide  valve  engine 
having  become  scored  and  worn  so  that  it  was  impossi- 
ble to  keep  packing  in  the  stuffing-box,  it  was  decided 
to  put  in  a  new  rod  and  substitute  a  set  of  metallic 
packing  for  the  old  fiber  article. 

The  rod  was  3^  inches  in  diameter  and  was  turned 
down  to  3  inches  where  it  was  fitted  in  the  crosshead 
and  secured  with  a  key.  But  that  rod  did  not  want  to 
be  removed;  in  fact  it  positively  refused  to  budge.  It 
seemed  to  feel  as  though  the  man  who  put  it  there 
twenty  years  ago  had  meant  it  to  stay,  and  stay  it  did. 
Backing-out  keys  were  of  no  avail,  and  only  served  to 
disfigure  the  crosshead,  and  gas  jets  used  to  expand 
the  crosshead  had  no  apparent  effect. 

Chain  tongs  were  also  brought  into  play,  but  while 
they  would  very  likely  have  twisted  the  rod  off  it 
would  not  come  out.  One  of  the  boys  remarked  that 
he  ''guessed  nothing  short  of  a  dose  of  water  in  the 
cylinder  would  fetch  the  old  thing  out/'  and  the  right 
idea  was  revealed. 

The  engine  was  placed  on  the  forward  or  crank 
center  and  the  slide  valve  moved  so  as  to  cover  the 

74 


REMOVING   A  TIGHT   PISTON-ROD  75 

back  steam  port  and  leave  the  forward  port  wide 
open.  A  i-inch  pipe  was  then  run  from  the  discharge 
of  a  small  feed  pump  and  connected  to  the  forward 
drip-cock  of  the  cylinder.  The  steam-chest  drips  were 
closed  and  the  piston-rod  packed  with  hemp. 

The  pump  was  then  started,  and  when  the  gage  on 
the  pump  registered  80  pounds  the  rod  walked  quietly 
out  of  the  crosshead.  As  an  1 8-inch  piston  has  an 
area  of  about  258.5  square  inches,  the  aggregate  force 
exerted  on  that  rod  was  over  10  tons.  The  writer 
therefore  desires  to  register  a  vote  in  favor  of  the 
water  cure  for  cases  of  stubbornness. 

CORE  SAND  IN  CYLINDER 

When  starting  a  new  engine  the  engineer  should 
satisfy  himself  that  everything  is  in  first-class  running 
order,  and  not  trust  to  the  assurance  of  the  erecting 
men  or  builders.  It  is  not  inferred  that  the  builders 
are  not  to  be  relied  upon,  but  a  great  many  things  that 
are  very  small  in  themselves  are  sometimes  overlooked, 
and  at  some  subsequent  time  give  rise  to  serious 
trouble  and  delay.  As  an  example  of  this,  an  engine 
which  had  recently  been  installed  and  had  been  run 
only  a  few  times  with  light  loads.  It  had  a  crosshead 
of  the  hollow  box  type,  the  bottom  guides  being  oiled 
by  the  oil  passing  down  through  the  crosshead  from 
the  top  guides  through  holes  drilled  for  that  purpose. 
An  emergency  arising,  the  engine  was  started  up  and 
a  heavy  load  thrown  on,  causing  the  engine,  which  had 
not  been  very  closely  adjusted,  to  pound  heavily.- 


76 


KNOCKS   AND   KINKS 


After  running  a  short  time  the  bottom  guides  began  to 
smoke,  and  before  the  engine  could  be  stopped  a  shower 
of  sparks  was  flying  from  the  guides. 

Investigation  showed  that  the  sand  remaining  from 
the  core  had  not  been  entirely  removed,  and  when  the 
engine  commenced  to  pound  it  had  dislodged  the  sand, 


FIG.  43 

which  naturally  found  its  way  out  with  the  oil  on  to 
the  guide.  It  required  a  lot  of  time  and  hard  work  to 
get  the  guides  and  crosshead  in  proper  order,  which 
would  have  been  avoided  by  a  careful  examination 
before  starting  the  engine. 

ADJUSTING  QUARTER-BOXES 

One  of  the  troubles  of  engineers  handling  engines 
having  the  quarter-boxes  adjusted  by  means  of  wedges, 


REMOVING   A   TIGHT   PISTON-ROD 


77 


as  shown  in  Fig.  43,  is  that  of  securing  and  maintaining 
accurate  adjustment  of  the  wedges.  The  following 
scheme  may  prove  of  value  to  some  of  the  boys:  Make 
four  brass  rings  or  collars,  as  shown  in  Fig.  44,  to  fit 


FIG.  44 

over  the  hexagon  nuts  on  the  adjusting  screws,  laying 
off  the  edges  in  twenty-fourths,  marking  the  spaces 
plainly. 

An  arrow  should  be  cut  in  the  cap  of  the  pillow-block 
as  a  registering  point.  Place  the  collars  on  the  nuts 
and  lower  the  wedges  until  the  bolts  are  free,  then 
draw  up  the  wedges  carefully,  being  sure  to  give  each 
nut  an  equal  number  of  turns,  until  the  proper  adjust- 
ment is  very  nearly  secured.  You  may  now  adjust  the 
bearing  by  twenty-fourths  of  a  turn  of  the  nuts,  and 
once  having  obtained  the  required  adjustment  it  will 
be  easy  to  take  up  the  boxes  quickly  and  accurately. 


XI 

SOME   MARINE   PRACTICE1 

THERE  are  lots  of  tricks  which  are  practised  in  the 
engine-rooms  of  steamships,  that  are  entirely  unknown 
to  the  average  stationary  engineer.  The  following  is 
a  sample. 

The  method  used  to  take  up  lost  motion  is  different 
from  what  is  usually  done  ashore.  Marine  engines  of 
the  propeller  type  are  usually  bolt  connected,  as  shown 
in  Fig.  45.  The  brasses  are  held  together  by  a  bolt' on 
each  side,  doweled  so  that  it  can't  turn  around.  The 
nuts  have  a  round  shank  fitting  into  an  enlarged  hole, 
with  a  set-screw  engaging  it,  as  shown  in  the  figure. 
Liners  are  placed  between  the  brasses,  mostly  made  of 
thin  brass  and  paper.  The  brasses  are  fitted  with  a 
little  room  at  the  sides,  so  that  they  can  be  moved 
back  and  forth  a  little,  endwise  of  the  pin.  (We  are 
dealing  now  with  crank-pin  boxes.) 

A  rough  and  ready  method  of  finding  how  slack  the 
box  is  consists  in  prying  it  back  and  forth  with  a  pivot- 
bar  inserted  between  the  brasses  and  the  crank  webs. 
Most  of  the  bearings  on  the  engine  can  be  tried  in  this 
manner,  with  the  exception  of  the  crank-shaft.  This 
endwise  motion  also  insures  a  better  running  engine,  as 

1  Contributed  to  Power  by  Eugene  L.  Griggs. 

78 


SOME  MARINE   PRACTICE 


79 


it  keeps  it  from  binding.  The  shaft  tends  to  work 
ahead  a  little,  through  the  wearing  of  the  thrust  bear- 
ing, and  if  everything  was  fitted  snug  there  would  be 
trouble  right  off. 

To  take  up  the  slack  on  a  crank-pin  box,  it  is  placed 
on  the  top  center,  as  the  pin  has  greatest  diameter  at 
this  point,  if  it  has  worn  any,  and  it  is  also  easier  to 


1/V/x 


FIG.  45 


FIG.    46 


get  at.  The  bottom  brass  is  then  lowered  down  about 
an  inch  by  partially  unscrewing  the  nuts  on  top.  A 
thin  liner  is  then  taken  out  from  each  side,  and  the 
bolts  set  up  solid  again.  It  is  just  the  same  as  though 
the  whole  bottom  end  of  the  connecting-rod  Were 
forged  in  one  piece.  The  nuts  on  top  are  marked  in 
some  way,  so  that  they  can  be  set  up  a  little  farther 
than  they  were  before,  also  they  can  be  put  back  just 
as  they  were  originally,  if  necessary.  There  must 
always  be  strain  enough  on  them  to  hold  the  liners  in 


8o  KNOCKS   AND   KINKS 

place.  The  nuts  are  moved  with  a  heavy  fork  wrench 
and  sledge. 

Leads  are  often  taken  off,  which  will  tell  exactly 
how  the  boxes  fit,  also  how  much  slack  there  is.  Fuse 
wire  is  used,  usually  about  No.  19,  English  wire  gage. 
This  wire  is  cut  in  lengths  a  little  less  than  half  the 
circumference  of  the  pin.  They  are  placed  in  position 
as  shown  in  Fig.  46.  Then  the  bolts  are  set  up  to  the 
marks  on  the  nuts,  squeezing  the  wire  out  flat  to  the 
thickness  of  a  piece  of  thick  writing  paper;  the  nuts 
next  slacked  up  and  the  leads  removed.  They  are 
then  tried  in  a  wire  gage,  and  should  be  from  28  to  32 
thick,  English  standard,  for  a  crank-pin  box  on  a  good 
sized  engine.  If  found  to  be  all  right  the  nuts  are 
screwed  up  to  the  original  marks. 

In  taking  down  the  boxes  (stripping  the  pin,  as  it  is 
called),  eyebolts  are  screwed  into  small  holes  tapped 
into  the  bolts,  tackles  hooked  on,  and  the  bottom  box 
lowered  down  into  the  crank  pit.  Then  a  block  of 
wood  is  adjusted  under  the  crosshead  to  take  the 
weight,  after  which  the  connecting-rod  is  swung  to  one 
side  and  the  top  box  removed. 

The  rod  is  generally  forked  at  the  top  with  a  bearing 
on  each  side.  In  taking  leads  the  top  boxes  are  re- 
moved, the  wires  inserted  and  the  boxes  placed  back 
again.  The  principle  is  the  same  as  the  bottom  end. 

The  crank-shaft  journals  (binders,  as  they  are  gen- 
erally termed)  are  treated  like  the  wrist-pin  boxes.  It 
is  always  advisable  to  take  leads  on  the  binders,  it 
being  impossible  to  pry  the  whole  shaft  back  and 
forth. 


SOME   MARINE   PRACTICE  8l 

All  propeller  engines  of  any  size  are  piped  up  so  that 
water  can  be  played  on  the  principal  bearings.  For 
the  crank-pins  there  is  a  pipe  with  holes  in  the  bottom, 
running  each  side  of  the  pin  at  right  angles  to  the 
shaft.  By  opening  a  cock  a  sheet  of  water  is  directed 
downwards  on  both  sides. 

The  main  journals,  besides  being  water-jacketed, 
have  a  pipe  suspended  over  them,  with  a  goose-neck 
joint,  allowing  it  to  be  moved  in  any  direction.  The 
eccentrics  are  treated  likewise.  Now  if  any  bearing 
starts  to  heat,  it  is  easily  kept  under  control,  because 
salt  water  is  so  cheap. 

The  guides  have  water  circulating  around  or  through 
them,  as  the  case  may  be  —  in  fact  most  engines  won't 
run  well  without  it. 

It  is  astonishing  what  a  small  stream  of  water  will 
keep  anything  cool  which  would  otherwise  run  hot. 
Salt  water  is  free  on  a  steamer,  and  a  small  pump  will 
jerk  it  overboard  again  without  much  trouble. 


XII 

RE-BABBITTING   LARGE   ENGINE   BOXES 

A  LARGE  engine  box  is  composed  of  four  pieces  and 
a  wedge,  and  some  of  the  larger  ones  have  two  wedges. 
Before  starting  the  job,  one  should  see  that  all  the 
necessary  tools  and  appliances  are  at  hand  and  one 
should  also  note  the  position  of  the  eccentric  and  see 
if  the  shaft  and  bottom  box  are  over  the  line.  In  all 
engines  there  is  a  "line  of  square"  on  the  bed  plate 
under  the  main  bearing  and  a  similar  line  on  the  bottom 
box,  the  latter  of  which  should  be  directly  over  the 
former.  The  time  to  make  them  so,  if  they  are  not,  is 
before  dismantling  the  box.  After  you  have  taken 
out  all  but  the  bottom  piece,  with  a  good  spirit  level 
examine  the  shaft  for  line  and  note  what  is  necessary 
if  anything  to  true  it;  then  slip  the  eccentric  and  fly- 
wheel, slack  off  the  nuts  on  the  outboard  bearing  and 
take  the  weight  of  the  shaft  off  the  bottom  piece  with 
a  good  jack.  The  shaft  may  be  blocked  up  then  and 
the  bottom  piece  drawn  out.  Run  the  babbitt  out  of 
the  bottom  piece  and  weigh  it  and  place  the  piece  on  a 
good  solid  bench  in  a  good  light,  and  where  it  may  be 
gotten  at  from  any  side.  Use  an  arbor  ^  of  an  inch 
in  diameter  smaller  than  the  shaft  and  set  the  liners 
on  each  end  of  the  box  so  that  you  can  get  TV  of  an 

82 


RE-BABBITTING   LARGE   ENGINE   BOXES  83 

inch  more  babbitt  than  before.  When  the  ends  and 
sides  are  secure  heat  the  babbitt  enough  to  char  a  pine 
stick  and  then  pour  it.  The  pouring  should  be  con- 
tinuous for  each  piece,  that  is,  all  at  one  time.  When 
cold  enough  the  arbor  may  be  removed.  With  a  heavy 
hammer  go  all  over  the  new  babbitt  and  hammer  it 
hard  to  make  it  firm;  then  dress  it  on  the  edges  some, 
after  which  the  sides,  top  and  edges  may  be  hammered. 
The  boxes  with  the  wedge  or  wedges  may  then  be 
clamped  together,  but  be  sure  that  the  outside  dimen- 
sions of  the  boxes  and  wedges  are  a  little  less  than  the 
inside  measurements  in  the  bed  plate.  Caliper  the 
shaft,  which  will  give  you  the  size  to  which  the  babbitt 
as  now  assembled  may  be  bored  out.  The  pieces  taken 
off  by  the  tool  may  be  caught  and  saved  by  spreading 
some  canvas  on  the  floor  under  the  lathe.  The  oil 
grooves  may  then  be  cut  with  a  diamond  pointed  cold 
chisel,  after  which  the  edges  of  the  grooving  should  be 
all  gone  over  with  a  file  to  make  sure  that  everything 
is  smooth.  The  bottom  box  may  then  be  put  back  in 
the  bed  and  after  oiling  it  well  the  shaft  may  be  put 
down  on  it.  At  this  point  the  shaft  should  be  trued  if 
it  is  necessary,  for  if  the  bottom  box  is  properly  placed 
the  rest  will  come  naturally  into  the  correct  position. 
Put  in  the  wedges,  if  there  are  two,  and  if  only  one  put 
in  the  back  side  piece  first,  and  when  all  are  in  give 
them  a  good  oiling.  A  box  that  was  re-babbitted  in 
the  manner  described  fourteen  years  ago  is  giving  good 
service  still.  It  has  given  no  trouble  during  this  time, 
and  promises  to  last  for  twenty-five  years  more. 


XIII 

KEYING  UP  CRANK-PINS 

CRANK-pins  and  bearings  heat  from  one  or  all  of  the 
following  causes:  First,  poor  lubrication;  second,  boxes 
not  being  properly  adjusted;  third,  out  of  line;  fourth, 
grit  or  other  foreign  substance  becoming  lodged  in  the 
bearings;  fifth,  crank-pin  and  bearings  not  sufficiently 
large  to  withstand  the  strain  imposed  upon  them  by 
the  action  of  the  reciprocating  parts.  Assuming  that 
the  pin  and  box  are  properly  proportioned  and  the  rod 
in  line,  let  us  begin  by  keying  up  the  crank-pin. 

Place  the  crank-pin  on  the  upper  quarter  and  revolve 
the  fly-wheel  in  the  opposite  direction  to  that  in  which 
it  turns  in  operation  for  about  one-eighth  of  a  revolu- 
tion. Slack  the  set-screw  and  you  will  find  that  a 
light  blow  from  a  soft  hammer  will  be  sufficient  to  take 
up  the  lost  motion  or  slackness  in  the  boxes.  In  some 
cases  the  key  can  be  pushed  down  by  hand  a  consider- 
able distance  without  the  use  of  the  hammer,  whereas, 
if  we  keyed  up  the  crank-pin  without  moving  the 
engine  in  the  opposite  direction,  a  sharp  blow  would 
be  required  to  move  the  key.  During  the  operation  of 
driving  the  key  if  one  hand  is  placed  beneath  the  key, 
one  can  readily  learn  the  weight  of  blow  that  must  be 
given  in  order  to  move  it.  Where  boxes  have  been 

84 


KEYING   UP   CRANK-PINS  85 

newly  fitted  we'  may  not  be  able  to  drive  the  key  to  its 
proper  position  at  the  first  keying.  Perhaps  an  engi- 
neer of  large  experience  might  be  able  to  drive  the  key 
the  required  amount  at  the  first  trial,  but  it  is  safer  to 
drive  it  gradually  until  we  arrive  at  the  required  posi- 
tion. Even  experienced  engineers  usually  drive  the 
key  a  little  at  a  time;  after  two  or  three  keyings  the 
position  is  found  where  the  pin  will  run  without 
pounding  or  heating. 

Some  engineers  drive  the  key  in  the  following  way: 
A  line  is  drawn  across  the  gib  and  key  about  half  an 
inch  above  and  parallel  with  the  strap,  as  shown  in 
Fig.  47  at  A  B.  Now  by  driving  the  key  we  can  readily 
see  how  far  the  line  upon  the  key  has  moved  from  the 
line  upon  the  gib.  A  lead  pencil  is  better  to  draw  the 
line  with  than  a  steel  scriber,  because  we  can  rub  out 
the  lines  at  will,  whereas,  if  we  use  a  steel  scriber,  the 
lines  drawn  from  time  to  time  will  become  confusing 
and  likely  to  lead  to  trouble.  Usually  the  key  is 
driven  about  -fa  to  TV  of  an  inch  at  each  keying. 
When  driving  the  key  in  a  large  engine  it  is  best  to 
jar  or  rock  the  fly-wheel  from  one-sixteenth  to  one- 
eighth  of  a  revolution  in  opposite  directions.  This 
enables  us  to  take  up  the  lost  motion  very  readily. 
During  the  operation  of  rocking  the  wheel  the  finger 
of  the  person  who  is  driving  the  key  can  be  kept  on 
the  space,  between  the  boxes,  as  shown  at  D,  Fig.  47, 
which  will  enable  him  to  detect  any  looseness  and  he 
will  continue  to  drive  the  key  until  all,  or  nearly  all,  of 
the  lost  motion  is  taken  up. 

Another  method  of  driving  the  key  is  to  drive  it 


86 


KNOCKS   AND   KINKS 


down  hard,  scribe  a  line  across  the  gib  and  key  and 
then  drive  it  back  about  -fa  of  an  inch  and  make  the 
set-screw  tight.  This  method  is  a  poor  one,  because 
one  is  liable  to  bind  the  boxes  on  the  pin. 

Another  method  often  successfully  employed  with 
light  connecting-rods  is  to  disconnect  the  connecting- 
rod  at  the  crosshead  and  let  an  experienced  man  rock 
it  up  and  down  while  another  strikes  the  key.  With 
a  little  experience  the  correct  position  of  the  key  can 


FIG.  47 

be  quickly  found  in  this  way.  After  the  correct  posi- 
tion is  found  it  is  desirable  to  draw  a  line  across  the 
gib  and  key  for  reference. 

Another  method  is  to  drive  the  key  partially  down ; 
then,  if  steam  is  up,  rotate  the  engine  slowly,  keeping 
your  finger  on  the  space  D,  as  before  mentioned,  and 
as  the  crank-pin  reaches  the  centers  tap  the  key  with 
the  soft  hammer  until  the  lost  motion  is  taken  up. 
The  finger  being  kept  upon  the  space  between  the  boxes 
enables  one  to  determine  when  the  correct  position  of 
the  key  is  being  approached.  It  is  clear  that  the  finger 


KEYING    UP   CRANK-PINS 


87 


cannot  be  kept  on  the  boxes  of  a  center  crank  engine, 
especially  if  the  space  between  the  disks  is  narrow.  If 
the  engine  runs  over,  the  half  box  farthest  from  the 
cylinder  should  be  well  chamfered  and  have  proper  oil 
grooves  cut  in  it.  If  it  runs  under,  then  the  half  box 
nearest  the  cylinder  should  be  well  chamfered  and 
have  proper  oil  grooves.  In  general  both  boxes  are 
chamfered  and  have  oil  grooves  cut  in  them.  The 
square  edge  should  not  be  allowed,  as  it  acts  as  a 


FIG.    48 

wiper.  The  square  edge  and  the  edge  that  is  cham- 
fered are  shown  in  section  in  Fig.  47  at  A  and  B, 
respectively. 

If  the  boxes  are  not  fitted  square,  they  are  apt  to 
bind  the  crank-pin  on  one  side,  producing  pounding 
and  heating.  Fig.  48  illustrates  this.  It  will  be  seen 
that  the  boxes  are  nearly  closed  at  A,  while  a  consid- 
erable amount  of  opening  is  shown  at  B.  It  will  be 
readily  understood  that  as  the  boxes  wear  they  will 
meet  at  the  point  A,  permitting  pounding  and  heating. 
Engineers  of  limited  experience  need  not  be  alarmed 
at  a  certain  amount  of  heat  in  their  crank-pin  boxes. 
Crank  pins  of  high-speed  engines  give  good  results, 
even  though  they  heat  sufficiently  to  make  it  uncom- 
fortable to  hold  the  hand  against  them.  Crank-pins 


88 


KNOCKS   AND   KINKS 


of  high-speed  engines  usually  heat  quicker  than  those 
of  slow  or  medium-speed  engines.  Suppose  we  have 
two  crank-pins  whose  diameters  are  equal,  it  can  be 
readily  seen  that  the  pin  on  the  higher-speed  engine 
will  traverse  a  greater  amount  of  surface  in  a  given 
time  than  the  pin  on  the  slower  speed  engine,  hence  the 
greater  liability  to  heat.  It  will  be  noticed  throughout 
that  the  sense  of  feeling  plays  an  important  part  in 
determining  the  position  of  the  key,  but  the  sense  of 
hearing  is  no  less  important. 

No  matter  how  well  the  bearings  are  fitted,  if  they 


FIG.  49 


FIG.  50 


are  not  properly  lubricated  they  will  heat.  Where 
glass  body  oil  cups  are  used,  engineers  or  oilers  are 
liable  to  believe  that  the  cups  are  working  properly 
because  they  see  the  oil  lowering  in  the  glass  body. 
Nevertheless  we  know  that  if  a  thread  of  waste,  a  hair 
or  other  similar  material  becomes  fastened  in  the  point 
of  ejection,  it  is  liable  to  lead  the  drop  of  oil  in  an 
entirely  opposite  direction  to  that  which  was  intended. 
Some  oil  is  "lumpy"  and  oil  that  has  been  used  and 
filtered  over  may  contain  water.  Also,  if  a  draft  of 
cold  air  is  allowed  to  blow  across  the  oil  cups,  it  will 


KEYING   UP   CRANK-PINS  89 

change  the  consistency  of  the  oil,  making  it  thicker 
and  less  liable  to  flow. 

All  these  things  should  be  taken  into  consideration 
in  order  to  prevent  heating  and  pounding.  The  square 
or  surface  plate  should  be  used  in  fitting  up  boxes.  If 
we  use  the  square  as  shown  in  Figs.  49  and  50,  we  can 
readily  discover  whether  the  boxes  are  square  or  other- 
wise. When  a  square  is  not  available,  the  calipers  may 
be  used.  Generally  a  surface  plate  can  be  improvised 
by  making  use  of  some  portion  of  the  engine  bed  or 
steam-chest.  If  this  cannot  be  done,  a  heavy  level 
board  may  be  used. 


XIV 

TESTING  FOR  A  LOOSE  CRANK-PIN1 

A  CERTAIN  engine  pounded  when  the  crank-pin 
passed  the  centers,  and  several  tests  were  applied  in 
efforts  to  locate  the  cause  without  success.  The  engi- 
neer was  convinced  that  the  crank-pin  was  loose,  but 
could  not  readily  prove  that  his  idea  of  the  matter 
was  correct.  The  pin  was  riveted  in  place,  and  where 
it  was  beaded  on  the  inside  of  the  disk  crank  there  was 
no  escape  of  oil  or  any  other  evidence  to  show  that  the 
parts  did  not  remain  in  perfect  contact. 

The  crank  was  placed  on  the  inside  center,  the  crank- 
pin  boxes  were  drawn  together  firmly  by  the  wedge 
provided  for  this  purpose,  and  the  crank  was  then 
turned  a  short  distance  by  a  lever  applied  to  the  fly- 
wheel; but  this  test  failed  to  turn  the  pin,  although  it 
was  carefully  marked  to  determine  how  much  it  moved. 

The  boxes  were  again  adjusted  to  working  conditions, 
the  crank  placed  on  the  inside  center,  and  steam  quickly 
admitted  to  each  end  of  the  cylinder  alternately.  Al- 
though there  did  not  appear  to  be  any  unnecessary  lost 
motion  while  the  engine  was  running,  this  test  showed 
much  more  than  was  expected,  making  it  impossible 
to  tell  whether  the  pin  was  loose  or  not. 

1  Contributed  to  Power  by  W.  H.  Wakeman. 
90 


TESTING   FOR  A   LOOSE   CRANK-PIN  91 

The  main-bearing  quarter-boxes  were  then  clamped 
firmly  to  the  shaft  by  screws  provided  for  this  purpose, 
and  the  test  again  applied.  Lost  motion  was  less  than 
before,  but  still  too  great  for  a  satisfactory  test  of  the 
pin.  Furthermore,  the  crank,  although  containing 
enough  cast  iron  to  make  it  apparently  very  strong, 
would  spring  badly  every  time  steam  was  applied  to 
the  piston,  and  there  was  enough  lost  motion  in  the 
crank-pin  boxes  to  prevent  a  satisfactory  test.  This 
was  taken  up  as  before,  after  which  a  square  was  held 
on  the  face  of  the  crank  and  against  the  end  of  the 
connecting-rod.  When  steam  was  again  applied  to 
each  end  of  the  cylinder,  a  slight  movement  of  the 
end  of  the  connecting-rod  plainly  indicated  that  the 
pin  was  loose. 

Of  course  the  crank  would  spring  every  time  pressure 
was  brought  to  bear  on  it  in  either  direction,  but  this 
movement  was  not  confounded  with  that  of  the  con- 
necting-rod, as  only  the  latter  indicates  the  condition 
of  the  pin. 

A  new  pin  was  roughed  out  and  then  turned  down 
nearly  to  the  correct  size  on  a  working  day.  On 
Sunday  the  old  pin  was  taken  out,  which  was  not  a 
difficult  job,  as  it  proved  to  be  loose  after  the  riveted 
head  was  cut  off,  and  it  had  been  loose  long  enough  to 
wear  the  hole  oblong,  making  it  necessary  to  rebore  it 
in  order  to  secure  a  perfect  fit. 

Investigation  showed  that  the  old  pin  had  been  put 
in  about  five  years  previous,  without  reboring  the  hole, 
although  the  pin  that  came  with  the  engine  was  loose 
enough  to  be  dangerous.  If  the  job  had  been  thor- 


92  KNOCKS--AND    KINKS 

oughly  done  at  that  time,  nothing  further  would  have 
been  needed;  but  in  addition  to  omitting  the  reboring 
of  the  old  and  worn  hole,  the  new  pin  was  simply 
driven  into  a  cold  crank  with  a  sledge  hammer,  and 
the  end  of  it  beaded  or  riveted,  which,  further  expe- 
rience taught,  is  not  sufficient  to  make  a  permanent  job. 
The  crank  should  be  heated  and  shrunk  onto  the  pin, 
especially  where  hydraulic  apparatus  is  not  available 
for  forcing  the  pin  into  place. 


XV 

TWO  NARROW  ESCAPES1 

THERE  are  illustrated  and  explained  in  the  mechan- 
ical papers  from  month  to  month  so  many  engine 
wrecks  in  which  lives  are  lost  and  much  valuable  prop- 
erty destroyed,  that  it  appears  as  if  an  engine  is  almost 
as  dangerous  as  a  boiler  at  the  present  time. 

These  illustrations  are  object  lessons  which  should 
lead  to  precautions  that  will  prevent  them  elsewhere, 
but  they  do  not  always  answer  this  purpose.  Two 
cases  are  presented  herewith  which  show  narrow  escapes 
from  serious  accidents,  and  as  other  engines  now  in 
service  may  be  found  in  the  same  condition,  if  a  remedy 
is  promptly  applied  in  every  such  case  it  will  save 
future  trouble  and  expense. 

A  certain  engine  pounded  badly  on  the  head  end 
occasionally,  but  never  on  the  crank  end.  This  is  one 
of  the  worst  kinds  of  pounds  to  locate,  as  it  may  not 
be  possible  to  find  it  when  heard,  and  when  a  search  is 
fairly  begun  it  disappears  as  if  by  magic. 

On  making  an  examination  of  the  external  parts, 
nothing  was  found  that  served  to  locate  the  pound. 
The  cylinder-head  was  removed  and  on  putting  a  socket 
wrench  on  one  of  the  follower  bolts  to  remove  it,  the 

1  Contributed  to*Power  by  W.  H.  Wakeman. 
93 


94 


KNOCKS   AND    KINKS 


whole  piston  and  rod  turned  together.  This  showed  at 
once  that  the  piston-rod  was  loose  in  the  crosshead, 
but  when  the  piston  was  turned  back  to  the  position  in 
which  it  was  found,  there  was  no  evidence  to  show 
where  trouble  was  to  be  found,  because  the  check-nut 
was  apparently  in  its  place,  although  not  duly  fastened. 
This  is  what  took  place  in  daily  practice.  When 
turned  to  the  position  in  which  it  was  found  there  was 


|o     o 

6 

o 


o 

o      o 


o      o 

O        O 


FIG.    51 

little  or  no  noise,  but  occasionally  the  rod  turned  out 
of  the  crosshead,  as  shown  in  Fig.  5 1 ,  until  piston  and 
cylinder-head  came  together,  causing  a  heavy  pound 
on  the  head  end  at  each  revolution.  Had  this  turned 
much  farther  it  must  have  caused  a  bad  wreck,  but  it 
would  turn  in  again,  stopping  all  noise  for  several 
hours,  after  which  the  trouble  would  be  repeated,  and 
this  had  continued  for  several  weeks.  Of  course  it  did 
not  take  long  to  put  the  piston  in  place  and  tighten 
the  check-nut  with  a  suitable  wrench,  but  it  was  a 
narrow  escape  from  serious  trouble. 


TWO    NARROW    ESCAPES 


95 


Figure  52  illustrates  another  case  in  which  there 
was  a  heavy  pound  once  in  each  revolution,  but  here 
it  was  on  the  crank  end.  This  was  a  larger  engine 
than  previously  mentioned,  as  it  developed  more  than 
1000  horse-power;  therefore,  every  time  it  was  shut 
down  and  its  internal  parts  examined  it  cost  several 
dollars. 

The  connecting-rod  is  a  tapering  fit  in  the  piston 


FIG.  52 

which  is  held  in  place  by  a  large  nut.  This  nut  became 
loosened,  hence  when  steam  was  admitted  to  the  crank 
end  of  the  cylinder  it  forced  the  piston  off  until  the 
nut  prevented  further  movement  at  this  point.  This 
jarred  the  whole  engine  and  caused  it  to  vibrate  badly, 
but  when  the  head  end  was  reached  and  a  charge  of 
steam  admitted  to  this  end  of  the  cylinder,  it  forced 
the  piston  on  again,  as  shown,  but  on  account  of  the 
tapering  rod  this  was  a  comparatively  easy  movement, 
making  little  noise. 


96  KNOCKS   AND   KINKS 

Of  course  this  was  a  very  dangerous  condition  of 
affairs,  but  the  engine  was  run  several  days  after 
efforts  had  been  made  to  locate  the  cause  of  trouble, 
until  an  expert  was  summoned,  discovered  the  loose 
nut,  and  tightened  it  in  about  five  minutes. 


XVI 

SOME  PRACTICAL   KINKS1 

EVERY  engineer  who  has  to  cut  and  fit  his  packing 
should  make  a  substitute  piston-rod.  This  can  be 
made  of  wood  and  of  different  diameters,  corresponding 
to  the  sizes  of  rods  found  in  the  plant.  Suppose  there 
are  four  different  diameters  of  rods,  then  the  substitute 


FIG.  53 

rod  will  have  the  appearance  shown  in  Fig.  53.  A 
piece  of  soft  pine  wood  may  be  employed  for  the  pur- 
pose. If  a  lathe  is  convenient,  place  the  piece  of  wood 
in  it  and  turn  it  down  to  correspond  with  the  diameters 
of  the  engine  or  pump  piston-rods,  as  the  case  may  be. 
If  the  distance  from  shoulder  to  shoulder  be  made  six 
inches,  and  there  are  four  different  diameters,  the  piece 
of  wood  will  be  twenty-four  inches  long. 

This  tool  will  be  found  to  be  very  handy;  instead  of 
waiting  for  the  engine  to  be  stopped  in  order  to  obtain 
the  length  of  the  piece  of  packing  needed,  the  size  may 
be  taken  from  the  wooden  rod  and  the  packing  cut  at 
leisure  without  danger  of  one's  being  burned  or  scalded. 

1  Contributed  to  Power  by  William  Kavanagh. 

97 


98 


KNOCKS   AND    KINKS 


Besides,  if  the  wooden  rod  is  accurately  made  the 
packing  can  be  fitted  to  a  finer  nicety  than  could  be 
done  by  wrapping  the  packing  around  the  actual,  hot 
piston-rod,  trying  to  locate  the  required  length.  Those 
especially  who  have  charge  of  compound  engines,  where 
the  cylinders  are  superimposed  on  each  other,  or  even 
where  the  cylinders  are  in  tandem,  will  find  this  sub- 
stitute rod  a  time-saver  as  well  as  an  accurate  tool. 


FIG.   54 

At  a  certain  plant  they  carry  two  hundred  pounds 
pressure  on  the  boilers  and  employ  reducing  valves. 
Two  of  the  compound  engines  are  supplied  with  steam 
at  150  pounds,  while  no  pounds  pressure  is  delivered 
to  the  Corliss  engines.  It  was  found  recently  that  one 
of  the  compound  engines  was  receiving  full  boiler  pres- 
sure, the  reducing  valve  being  inoperative.  Investi- 
gation disclosed  that  the  rods  supporting  the  springs 
were  corroded,  and  that  all  the  valve  needed  was  a 


SOME   PRACTICAL   KINKS  99 

little  oil  in  the  guides  through  which  the  rods  passed. 
The  reducing  valve  is  shown  in  Fig.  54.  The  corroded 
parts  were  at  A  A1. 

There  is  a  common  exhaust  main  for  all  of  the  en- 
gines, and  included  in  the  line  is  the  elbow  at  M, 
Fig.  55,  which  had  a  bad  habit  of  breaking;  it  had  to 
be  renewed  three  times.  Different  ideas  were  expressed 
with  respect  to  the  cause  of  the  breaks.  Some  said  it 
was  water-hammer,  others  said  the  castings  were  bad 
and  so  on.  The  cure  was  easily  affected  by  inserting 
an  expansion  joint,  as  shown  at  P. 

Heine  boilers  are  used  and  each  boiler  is  fitted  with 
a  pop  safety  valve.  Through  some  accident  or  because 
of  poor  management  the  safety  valve  on  boiler  No.  i 
used  to  blow  continuously.  No  amount  of  tension  on 
the  spring  would  stop  the  blowing,  so  it  was  deter- 
mined to  take  the  valve  off  and  ascertain  the  difficulty. 
A  substitute  valve  was  bolted  in  position  so  the  boiler 
could  be  used  in  the  meantime.  Inspection  of  the  old 
valve  showed  that  the  seat  was  badly  cut;  more  than 
a  dozen  grooves  had  been  eaten  into  it  by  the  action 
of  the  steam.  The  disk  was  also  badly  grooved. 

One  of  the  engine-room  assistants  was  detailed  to' 
grind  out  the  grooves,  the  method  employed  being  as 
follows:  A  piece  of  pine  wood  about  half  an  inch  thick 
was  attached  to  the  back  of  the  valve  disk  by  means 
of  two  i-inch  tap-bolts,  as  shown  in  Fig.  56.  On  top 
of  this  piece  of  wood  was  fastened  a  J-inch  pipe  flange 
into  which  was  screwed  a  piece  of  J-inch  pipe  of  suffi- 
cient length  to  reach  about  two  feet  above  the  bottom 
of  the  valve.  Diametrically  across  the  valve  body  was 


IOO 


KNOCKS   AND   KINKS 


bolted  a  section  of  pine  board  in  which  had  been  drilled 
a  hole  to  coincide  with  the  valve  center.  The  J-inch 
pipe  extended  through  this  hole,  the  sides  of  which 


SOME  PRACTICAL   KINKS 


101 


acted  as  a  guide  for  the  pipe.  A  carpenter's  brace  was 
fitted  to  the  i-inch  pipe  and  by  turning  the  brace  to 
either  the  right-  or  left-hand,  the  valve  disk  was  made 
to  assume  a  corresponding  motion. 

Ground  glass  and  machine-oil  composed  the  cutting 
agent.  By  raising  the  valve  disk  the  seat  could  be 
painted  with  the  ground  glass  and  oil.  Then  the  disk 
was  lowered  and  its  rotation  effected  by  the  means 


FIG.    56 

described.  The  grinding  process  was  kept  up  until  all 
of  the  grooves  were  worn  away.  The  ground  glass  was 
then  dispensed  with  and  oil  was  used  alone  in  the 
finishing  process.  It  took  considerable  time  but  the 
job  was  so  satisfactory  that  it  paid.  If  a  lathe  had 
been  at  hand  some  time  could  have  been  saved,  al- 
though in  any  case  the  disk  would  have  to  be  ground 
to  the  seat.  The  oil-finishing  process  develops  a  highly 
polished  surface  that,  in  all  probability,  cannot  be 
surpassed  by  any  other  method. 

An  accident  occurred  to  the  stuffing-box  of  one  of 


102 


KNOCKS   AND    KINKS 


our  high-speed  engines,  the  stud-bolts  being  broken  off 
close  to  the  cylinder-head.  Owing  to  the  fact  that 
there  is  a  diaphragm  in  front  of  the  stuffing-box,  the 
stud-bolts  could  not  be  drilled  out.  The  stuffing-box 
is  cast  in  the  plug,  which  is  fitted  into  the  cylinder-head, 
as  shown  in  Fig.  58,  and  it  was  withdrawn  as  .follows: 
A  heavy  piece  of  timber,  for  a  brace,  was  bolted 
across  the  cylinder-head,  having  a  hole  central  with 
the  stuffing-box  center,  as  shown  in  Fig.  57.  A  j-inch 
iron  rod  of  sufficient  length  to  reach  from  the  stuffing- 


o          O 


o 
FIG.  57 


FIG.    58 


box  to  the  wooden  brace  was  threaded  on  both  ends 
and  nuts  and  washers  attached.  By  screwing  up  the 
nut  at  B,  Fig.  58,  the  plug  was  easily  drawn  into  the 
cylinder.  The  old  stud-bolts  were  then  drilled  out 
and  new  ones  inserted.  It  will  be  noticed  that  the 
taper  or  plug  looks  toward  the  crank  end,  so  that  the 
steam  always  exerts  a  pressure  to  maintain  the  plug 
in  position. 

The  engineers  who  erected  this  plant  made  a  serious 
mistake  with  one  of  the  Corliss  engines.  The  holding- 
down  bolts  were  more  than  six  inches  too  short  and  to 
remedy  the  mistake  sockets  were  screwed  on  one  end 
of  the  bolts,  into  which  were  screwed  short  bolts  to 


SOME  PRACTICAL   KINKS 


103 


make  up  the  deficiency.  Fig.  59  shows  one  of  the 
original  holding-down  bolts  with  socket  and  short  bolt 
attached.  Later  the  sockets  on  the  holding-down  bolts 
of  the  outboard  bearing  stripped,  and  it  was  at  first 


FIG.    S9 


thought  that  in  order  to  renew  those  sockets  the  fly- 
wheel, shaft  and  bearing  would  have  to  be  removed. 
The  foundation  of  the  outboard  bearing  is  built  in 
line  and  close  to  the  buttressed  portion  of  the  engine- 
room  wall,  as  shown  in  Fig.  60.     At  A  is  a  plan  view 


FIG.   60 

of  the  bearing,  shaft  and  fly-wheel.  The  fly-wheel  is 
fourteen  feet  in  diameter  and,  of  course,  the  removal 
of  this  machinery  would  entail  considerable  expense, 
not  to  mention  loss  of  time.  A  section  of  heavy  plank 
B  was  secured  to  the  wall  by  means  of  expansion  bolts. 
A  piece  of  planking  three  inches  thick  and  twelve 


104  KNOCKS   AND    KINKS 

inches  wide  was  adjusted  from  the  wall  to  the  bearing 
C.  This  plank  was  spiked  to  B,  and  was  sufficiently 
long  to  prevent  movement  of  the  bearing  in  that 
direction.  v 

This  part  of  the  problem  was  easy,  but  to  prevent 
movement  of  the  bearing  in  the  opposite  direction  was 
where  the  difficulty  lay;  many  ideas  were  tried  out 
before  the  plan  adopted  was  evolved.  Three  2-inch 
nipples  were  cut  to  fit,  as  shown  at  D  E  F,  the  long 
nipple  E  being  right-and-left.  The  elbow  at  F  was 
made  left  because  the  pipe  tongs  could  be  employed  to 
screw  up  the  nipple  E  in  the  direction  of  the  bearing. 
A  heavy  strain  was  brought  to  bear  upon  the  nipples 
D  and  F  by  screwing  up  the  nipple  £.  After  this  was 
done  the  nipple  E  was  wedged  in  place  by  means  of 
blocks  of  wood  in  order  to  prevent  vibration  when  the 
engine  was  running.  The  engine  is  now  running  satis- 
factorily and  to  all  appearance  this  bearing  will  need 
no  further  strengthening. 


XVII 

HOW  A  NOISY  PISTON  VALVE  WAS  CURED  * 

IN  a  certain  plant  there  are  three  high-speed  en- 
gines of  a  prominent  make,  which  are  belted  to 
three  Mather  dynamos  and  are  used  for  lighting 
and  power  purposes.  During  the  summer  season 
two  of  the  engines  are  sufficient  for  all  require- 
ments, but  during  the  winter  all  the  engines  are  re- 
quired. The  engines  and  dynamos  are  designated  as 
Nos.  i,  2  and  3.  No.  i  was  built  about  ten  years  ago, 
and  was  installed  in  the  plant  some  time  before  Nos.  2 
and  3.  Owing  to  this,  No.  i  is  worn  in  the  cylinder, 
valve  chamber  and  bearings  to  a  greater  degree  than 
the  others.  At  the  time  the  writer  took  charge  of  this 
plant  he  noticed  that  Nos.  i  and  3  were  run  almost 
constantly.  Upon  inquiring  why  No.  2  was  not  run, 
he  was  informed  that  she  was  belted  to  an  "  explosive 
dynamo,"  and  for  this  reason  she  was  only  run  during 
the  time  the  other  engines  required  to  be  cleaned  or 
keyed.  How  No.  2  was  cured  of  her  explosive  propen- 
sities appeared  in  a  previous  issue  of  Power,  in  "  Some 
Things  Worth  Knowing,"  The  noise  or  "grunting" 
of  No.  i  attracted  the  attention  of  the  writer  the 
moment  he  entered  the  engine  room.  Upon  asking 

1  Contributed  to  Power  by  William  Kavanagh. 


106  KNOCKS   AND    KINKS 

why  the  engine  was  allowed  to  run  without  oil  —  this 
being  his  first  impression  —  he  was  informed  that  "All 
the  men  in  this  country  could  not  do  anything  with 
her  to  stop  the  noise.  She.  made  that  noise  since  the 
day  she  was  first  started,"  and,  furthermore,  "the  local 
expert  had  the  indicator  on  the  engine  to  try  and 
discover  the  difficulty."  The  expert  suggested  that 
a  new  valve  and  valve  chamber  be  sent  for,  but  the 
fact  that  the  builder  of  this  engine  was  over  400  miles 
away,  and  also  that  the  engine  would  have  to  be  shut 
down,  precluded  any  possibility  of  making  the  change. 
The  owner  of  the  engine  was  satisfied  to  have  all  of 
the  local  machinists  and  experts  try  and  stop  the 
"grunting,"  but  they  never  succeeded.  The  writer, 
after  becoming  acquainted  with  the  plant,  determined 
to  see  if  he  could  do  anything  to  lessen  the  noise.  The 
first  thing  he  did  was  to  order  three  hand  oil  pumps, 
one  for  each  engine.  No  i  received  special  attention. 
Oil  was  pumped  into  the  valve  chamber  regularly,  but 
there  was  no  decrease  in  the  noise.  The  cylinder  oil 
was  changed,  and  in  one  case  6  pints  of  cylinder  oil 
were  pumped  into  the  valve  chamber  without  causing 
the  slightest  effect  on  the  noise.  From  this  it  was  quite 
apparent  that  something  must  be  done  besides  pump- 
ing oil  into  the  cylinder.  When  an  opportunity  oc- 
curred, the  bonnet  of  the  valve  chamber  was  removed 
and  the  valve  inspected.  At  first  sight  there  was  no 
apparent  reason  why  the  valve  should  make  any  noise. 
The  valve  was  highly  polished  and  showed  plenty  of 
lubrication.  Fig.  61  is  a  longitudinal  elevation  of  the 
valve  and  valve  chamber.  The  valve  is  admitting 


HOW   A   NOISY   PISTON-VALVE   WAS   CURED      107 

steam  to  the  cylinder  through  the  ports  B  and  is 
exhausting  at  the  end  D  through  the  passage  E.  The 
guide  K  is  bolted  fast  to  the  rod  that  maintains  the 
cylindrical  parts  of  the  valve  in  position.  Fig.  62  shows 
how  the  guide  K  was  constructed.  It  will  be  noticed 
that  the  leg  or  sliding  part  of  the  guide  shown  at  P  is 


FIG.    6l 


FIG.    64 


worn  away  about  T3^  inch.  From  the  appearance  of 
the  guide  and  guide-way,  which  is  shown  in  Figs.  63 
and  64,  it  is  evident  that  they  were  placed  in  the  valve 
chamber  by  the  builder,  and  it  would  be,  or  might  be, 
wrong  to  meddle  with  it;  so  it  was  determined  to  try 
some  other  means  before  attempting  to  remove  or 
meddle  with  it.  To  remove  the  valve  from  the  cham- 
ber necessitated  the  removal  of  K.  Before  the  valve 


108  KNOCKS   AND    KINKS 

was  removed  the  "lead"  was  noticed.  The  lead  on 
the  head  end  was  J  inch,  while  on  the  crank  end 
the  lead  was  hardly  noticeable.  After  the  valve  was 
removed  it  was  inspected  thoroughly  and  calipered  to 
locate  the  worn  side.  No  fault  being  found,  the  valve 
was  replaced.  The  engine  being  on  the  inboard  center, 
the  valve  was  given  ^  lead,  then  the  engine  was 
turned  over  to  the  outboard  or  crank  center  to  test 
for  the  lead.  Now  it  was  immediately  noticed  that 
the  engine  could  not  be  turned  over  on  to  the  crank 
center  without  breaking  the  valve  rod,  because  the 
"horns"  or  guides  shown  at  D,  Fig.  61,  struck  the 
stuffing-box  head  of  the  valve  chamber.  This  was 
indeed  a  discovery,  so  the  valve  had  to  be  replaced  as 
found,  as  the  engine  was  needed  to  meet  the  evening 
load. 

Now  we  see  we  have  discovered  at  least  two  things: 
First,  that  the  guide  K  is  worn  all  at  one  side;  second, 
that  there  is  a  structural  mistake  in  the  valve  or  valve 
chamber.  Before  the  bonnet  was  replaced  the  valve 
and  chamber  were  smeared  with  cylinder  oil  and 
plumbago  and  the  engine  started  for  the  night.  The 
next  day  the  valve  was  removed  and  j  inch  sawed  off 
from  the  horns,  as  shown  at  D,  which  permitted  the 
valve  to  be  properly  set.  While  the  valve  was  out  of 
the  chamber  staggered  grooves  were  filed,  as  shown  at 
F,  around  the  cylindrical  parts  of  the  valve.  It  was 
not  considered  expedient  to  file  complete  circles.  After 
the  grooves  were  filed  the  valve  was  replaced  with 
proper  lead  on  both  centers,  the  engine  was  started, 
and  the  noise  was  considerably  reduced,  together  with 


HOW  A   NOISY   PISTON-VALVE   WAS   CURED 


109 


a  saving  of  300  pounds  of  fuel  in  twelve  hours,  the 
load  being  the  same.  Now  that  the  grunting  did  not 
vanish  altogether,  the  writer  could  not  reconcile  him- 
self to  the  guide  K.  He  reasoned  in  this  way  against 
the  guide,  that  a  piston  valve  should  be  free  to  rotate  if 
necessary,  and  that  the  guide  K  prohibited  the  valve 


FIG.   65 


1  IJ 


FIG.   66 


from  finding  its  own  center  or  riding  position;  so  he 
resolved  to  dispense  with  the  guide  altogether.  In 
order  to  do  this  it  was  necessary  to  make  a  yoke  to 
maintain  the  valve  stem  in  position.  A  piece  of  heavy 
sheet  copper,  which  was  the  only  available  metal,  was 
used.  The  heavy  lines  in  Fig.  65  show  the  copper 


FIG.    67 

yoke;  the  dotted  lines  show  the  builders'.  It  is  self- 
evident  that  the  copper  yoke  must  be  put  on  in  the 
reverse  direction  to  that  of  the  builders'  in  order  to 
maintain  the  valve-stem  in  position  should  the  valve 
rotate  or  require  to  be  rotated  by  hand.  Referring  to 
Fig.  66  we  see  the  valve-stem  is  fitted  with  a  square 
nut  on  the  end,  which  nut  is  shown  behind  the  copper 
yoke  in  dotted  lines.  Now  it  can  be  seen  that  the 


no  KNOCKS   AND   KINKS 

square  corners  of  the  nut  must  be  preserved  if  we 
desire  to  be  able  to  rotate  the  .valve  by  hand.  If  we 
look  at  Fig.  67  we  will  see  that  the  hole  in  the  cross- 
head  that  operates  the  valve  and  stem  is  enlarged,  and 
the  lock-nuts,  as  shown,  permit  the  stem  to  be  rotated. 
Now,  since  the  square  nut  prohibits  the  valve  from 
rotating  it  is  evident  that  rotation  takes  place  in  the 
crosshead  between  the  lock-nuts,  as  indicated.  Every- 
thing being  ready,  the  valve  was  put  in  position  without 
the  guide  K,  and  all  the  grunting  vanished. 


XVIII 

EMERGENCY  REPAIRS  AND  RUSH  JOBS 

IN  time  of  trouble,  the  man  who  can  take  hold  and 
come  out  with  the  nearest  to  a  permanent  repair  is 
the  one  who  will  win  out  in  the  end  every  time.  In 
all,  or  nearly  all,  break-down  jobs  there  are  usually 
several  ways  of  making  repairs,  and  all  may  be  very 
good,  but  the  man  who  has  a  large  plant  waiting  for 
him  to  do  something  is  not  usually  going  deeply  into 
the  various  ways  of  performing  a  piece  of  work,  but 
will  usually  satisfy  himself  that  the  way  he  has  out- 
lined will  do  the  work,  and  then  go  on  and  finish  it 
without  departure  from  his  original  method. 

One  of  the  worst  things  to  contend  with  is  a  broken 
shaft.  This  piece, of  shafting  was  used  as  a  jack  shaft, 
and  carried  on  one  end  an  18  x  6o-inch  pulley  with  an 
1 8-inch  double  belt,  and  on  the  other  a  24  x  72-inch 
pulley  which  ran  a  gang  edger.  This  shaft  was  3}^ 
inches  diameter,  about  14  feet  long,  and  was  carried 
in  three  bearings,  a  center  and  two  end  ones.  The 
bearings  were  all  on  bridge-trees  and  keyed  in  by 
wedges  that  were  driven  in  from  the  side  next  to  the 
draft,  instead  of  the  rear  side.  One  evening  it  was 
noticed  that  the  machine  on  this  shaft  slowed  down 
and  stopped,  and  very  naturally  it  was  supposed  the 


112  KNOCKS   AND    KINKS 

belt  had  come  off.  A  hasty  examination  showed  that 
the  shaft  was  broken  in  two  in  the  center  bearing  and 
the  collars  on  each  end  had  prevented  its  coming  out. 
A  piece  of  8-inch  pipe  was  placed  in  a  lathe  and 
bored  out  for  about  i  inch  to  the  depth  of  TV-inch  cut. 
Both  ends  were  turned  the  same  and  then  a  piece  of  old 
dead  plate  out  of  a  furnace  door  about  i  inch  in  thick- 
ness was  bored  out  to  shaft  size;  then  the  outside 
turned  off  to  the  size  of  the  bored-out  pipe  end.  Two 
of  these  were  made.  Then  the  middle  bridge-tree  was 
taken  out  of  the  way  and  the  shaft  center  was  blocked 
up  until  it  was  level;  a  top  side  line  run  on  it  and  it 
was  made  perfectly  straight.  Before  this  was  done, 
however,  one  of  the  collars  had  been  slipped  over  the 
shaft  (one  on  either  side  of  the  break)  and  then  the 
pipe  was  put  on  over  shaft  also.  Then  the  shaft  was 
lined  as  explained  before,  the  pipe  divided  on  either 
side  of  the  break,  the  collars  drove  into  the  ends  of 
the  pipe  and  then  ran  the  whole  full  of  babbitt  metal. 
When  the  pipe  was  in  the  lathe  a  place  was  turned  in 
the  center  long  enough  for  a  bearing,  and  when  the 
pipe  was  run  full  of  metal  the  center  bridge-tree  had 
only  to  be  let  down  far  enough  to  take  in  the  tail 
bearing  of  an  old  engine  we  had,  that  had  been  through 
a  fire,  babbitt  the  same,  and  the  job  was  practically 
done.  After  the  babbitt  had  cooled  sufficiently,  two 
holes  were  drilled  through  the  pipe  and  shaft  and  two 
i -inch  machine-steel  pins  were  driven  in  and  was 
ready  to  start.  The  job  lasted  until  we  got  a  new 
shaft  from  St.  Louis,  and  when  the  new  one  came  we 
did  not  put  it  in  right  away.  In  Figs.  68  and  69  a 


EMERGENCY   REPAIRS   AND   RUSH    JOBS         113 

sectional  view  of  the  repair  after  it  was  finished  is 
given.  It  wasn't  very  pretty,  but  it  did  the  work,  and 
that  was  all  we  wanted  it  to  do,  and  it  seemed  strong 
enough  to  have  lasted  much  longer  than  we  used  it. 

A,  center  bearing  box;  B,  piece  of  8-inch  pipe;  D, 
babbitt  lining  between  pipe  and  shaft  (head  removed 

SECTION  THROUGH   a-b 


FIGS.  68  and  69 

in  lower  view) ;  5,  shaft ;  C,  pins  that  go  through  shaft ; 
H,  cast-iron  head,  light  driving  fit  in  end  of  pipe. 

Trouble  was  had  with  a  large  compound  circulating 
pump  on  account  of  it  losing  so  many  valves  and  valve 
studs.  The  studs  were  very  light  on  the  lower  end, 
would  break  off  on  the  slightest  provocation  and  then 
both  valve  and  stud  would  go.  On  account  of  the  way 
the  top  of  the  water  end  was  made  it  was  impossible  to 
get  to  the  studs  to  drill  them  out  when  they  were 
broken  off  without  taking  off  the  whole  top  of  the 


KNOCKS   AND    KINKS 


pump,  and  that»was  too  big  a  job  to  try  to  do  in  one 
day.  As  we  were  almost  compelled  to  run  condensing 
or  shift  part  of  our  load  to  another  station,  the  breaking 


No.4 


SECTION  THROUGH  C  d  IN  Fin.  4 

y/////mvmm/////A 

1                A               1 

FIGS.  70  and  71 

of  these  studs  became  a  serious  thing.  In  correcting 
the  trouble  the  arrangement  for  holding  the  valves 
in  that  is  shown  in  Figs.  70  and  71  was  designed. 
All  the  old  valve  studs  were  removed,  a  drill  run 


EMERGENCY   REPAIRS   AND   RUSH   JOBS          115 

through  all  the  threaded  holes  into  which  they  had 
formerly  been  screwed.  This  hole  was  drilled  entirely 
through  the  upper  valve  plate,  and  as  the  suction 
valves  were  directly  underneath  the  discharge,  we 
drilled  on  into  the  suction  valve  plate  deep  enough  to 
remove  all  traces  of  threads,  but  did  not  go  through 
the  suction  plate.  Then  all  holes  were  reamed  and 
the  end  of  all  studs  were  made  a  snug  fit  where  they 


FIG.    72 

went  through  the  valve  plate.     A  joint  was  made  on 
the  plates  with  the  shoulder  shown  on  the  studs. 
A  A  A  A   =   Bonnets,  both  discharge  and  suction. 
B  B  B  B    =  Cast-iron  body  of  water  end  of  pump. 
C  C  C  C     =  One-inch  bolt  threaded  into  the  discharge 

plate  and  holding  down  crossbars  across 

the  top  of  all  four  valves. 
D  D  D  D   =   Bridges  extending  from  one  valve  stud 

to  another. 
0  0  O  0     =   Pins  that  go  through  bridges  and  into 

top  of  studs. 
E  E  E  E    =  Studs  that   hold  soft   rubber  valves  in 

place. 


n6 


KNOCKS   AND   KINKS 


yyy  y   =  Valves,    16  in  number  and  all  held  in 

place  by  two  i-inch  studs. 

Figure  72  shows  a  very  useful  device  that  is  for  the 
purpose  of  pulling  the  cranks  off  of  Corliss  engine  valve 
stems.  The  sketch  explains  itself.  A  A  are  hooks  to 
catch  on  inside  of  bonnet,  D  D  is  a  center,  of  which 
various  lengths  can  be  used  in  order  to  bring  the  jack 
within  range  of  different  size  engines. 

ENGINE  REPAIRS 

Here  are  a  couple  of  safety  appliances  which  we  put 
on  our  Allis  cross-compound  Corliss  engine: 

Have  read  of  an  engine  being  wrecked  by  the  break- 


FIG.  73 

ing  of  the  bolt  which  held  the  crosshead  shoe  in  place. 
On  the  out  stroke  the  bottom  shoe  slipped  from  under 
the  crosshead  and  on  the  return  stroke  it  was  caught 
between  the  crosshead  and  the  cylinder,  causing  a 
wrecked  engine. 

To  guard  against  this  happening  to  our  engine,  we 


EMERGENCY   REPAIRS   AND   RUSH   JOBS          117 

drilled  and  tapped  three  holes  in  the  end  of  each  shoe 
and  bolted  a  piece  of  J-inch  iron  across  the  end,  as 
shown  at  a,  Fig  73,  so  that  if  the  bolt  b  should  break, 
the  shoe  could  not  slip  from  under  the  crosshead  and 
cause  any  damage,  but  would  give  us  warning  to  shut 
down. 

On  the  crosshead  end  of  the  connecting-rod,  which 
is  of  the  solid-end  style,  as  shown  in  Fig.  74,  there  is 
some  danger  of  the  upper  bolt  breaking  and  letting  the 


m 


wedge  drop  down,  which  would  cause  the  shutting 
down  of  the  engine  possibly  at  just  the  time  when  it 
is  most  needed. 

As  a  precaution  against  this,  we  drilled  two  holes 
through  the  washer  c  and  drilled  and  tapped  two  holes 
in  the  bottom  of  the  rod  to  receive  bolts  a  and  a' . 
Then  after  getting  the  wedge  nicely  adjusted  we  took 
a  careful  measurement  of  the  space  between  the  bottom 
of  the  wedge  and  the  bottom  of  the  rod,  and  had  a 
piece  of  wrought-iron  tube  cut  the  proper  length,  so 
that  when  it  was  put  in  as  at  B,  Fig.  74,  it  would  be 
a  snug  fit  between  the  washer  and  the  wedge.  If  the 


n8 


KNOCKS   AND    KINKS 


upper  bolt  should  break,  the  washer  and  piece  of  tube 
would  keep  the  wedge  up  in  place. 

When  having  to  draw  the  wedge  up  farther  to  make 
up  for  the  wearing  of  the  brasses  and  pin,  a  liner  can 
be  placed  between  the  washer  and  the  piece  of  tube. 

On  a  Rice  &  Sargent  engine  with  rod  made  like 
Fig.  75,  the  bolt  A  broke  above  the  wedge  and 


^—^ 


FIG.  75 

allowed  the  wedge  to  fall,  causing  a  shut-down  when 
the  engine  was  very  much  needed. 

As  a  quick  repair  job  a  piece  of  ij-inch  rod  was 
threaded  to  fit  the  wedge  and  was  screwed  through  the 
wedge  with  a  Stilson  wrench  until  it  brought  up  against 
the  bottom  of  the  rod;  then  a  few  more  turns  and  the 
wedge  was  brought  up  tight  enough  and  the  engine 
was  ready  for  a  start. 

When  ordering  a  new  bolt,  they  had  one  made  long 
enough  so  that  the  end  of  it  would  just  ^  touch  the 
bottom  of  the  rod,  leaving  no  chance  for  the  wedge  to 
get  away  again. 

A  most  ingenious  and  effective  repair  job  is  that 
shown  in  Fig.  76.  The  break  occurred  to  an  old- 
fashioned  box  bed  type  of  engine,  a  crack  developing 


EMERGENCY   REPAIRS   AND   RUSH    JOBS          119 

under  the  main  bearing  at  A  and  gradually  extending 
downward  until  a  clean  break  was  made  in  both  sides 
of  the  bed. 

Had  the  cap  of  this  bearing  been  made  and  fitted  as 


1 

1  p-  1 

i  —  ;) 

---  -"• 

"O  °                        °  O 

V  o  , 

MAIN  FEARING  CAP 

o  *                  °  o 

F 

>-     -0 

TOP  VIEW 

L 

FIG.    76 


shown  in  Fig.  77,  it  is  hardly  probable  that  the  crack 
would  ever  have   appeared,   as   the   lips  of  the   cap 


120 


KNOCKS   AND   KINKS 


fitting  over  the  lugs  on  the  bed  would  have  held  and 
strengthened  the  bed  casting. 

As  it  was  imperative  that  the  plant  should  continue 
in  operation  with  the  least  possible  delay,  and  it  would 
have  taken  several  weeks  at  least  to  install  a  new 
engine,  it  was  decided  to  attempt  temporary  repairs. 

A  rectangular  hole  4  x  IT\  inches  was  made  in  each 
side  of  the  bed  at  B  and  the  corners  of  the  bed  squared 
up  at  C.  Two  bars  of  4  x  ij-inch  iron  were  then 
made  with  the  ends  bent  as  shown  at  D,  the  distance 


DDL 


FIG.  77 

between  angles  being  less  than  the  distance  between 
B  and  C  by  the  amount  of  opening  at  the  break. 

The  bars  were  then  heated  to  a  red  heat,  care  being 
taken  not  to  heat  them  at  the  angles,  and  they  were 
then  shoved  into  place,  as  shown  in  Fig.  76,  and 
allowed  to  cool  off,  the  shrinkage  of  the  bars  drawing 
the  sections  of  the  bed  together  so  that  the  crack  was 
hardly  noticeable. 

A  cast-iron  bracket  E  was  then  made  and  bolted  to 
the  top  of  the  engine  bed,  as  shown  in  Fig.  76,  the 
flange  or  lug  of  which  extended  out  over  the  sides  of 
the  bed,  as  shown  in  the  top  view,  holes  being  cored  in 


EMERGENCY   REPAIRS   AND   RUSH    JOBS          121 

the  casting  to  receive  the  stay-rods  F  F,  which  were 
made  of  2i-inch  square  iron,  one  end  being  bent  and 
made  in  the  form  of  a  hook  to  fit  over  the  heading  at 
the  top  of  the  bed  at  G. 

The  bracket  ends  of  the  rods  were  turned  and 
threaded  to  receive  nuts  as  shown,  and  an  offset  put 
in  the  rods  to  enable  them  to  clear  the  bolts  in  the 
cap.  The  block  H  was  placed  under  the  rods  to  pre- 
vent their  bearing  on  the  cap,  and  was  secured  by  a 
dowel  pin  in  the  rod. 

When  finished  and  the  nuts  properly  tightened  the 
engine  was  probably  stronger  and  more  serviceable 
than  before  the  break  occurred,  and  is  still  in  that 
condition. 


XIX 


TEMPORARY   REPAIR  TO   BROKEN   SHAFT 

THE  enclosed  sketch,  Fig.  78,  shows  how  a  quick 
repair  was  made  to  a  broken  shaft.  The  shaft  was 
used  for  driving  two  printing  machines  and  an  ink 


FIG.  78 

mill.  It  was  owing  to  the  ink  mill  becoming  locked 
that  the  shaft  had  broken.  The  broken  shaft  was 
uncoupled,  so  that  the  rest  of  the  works  could  run. 
The  broken  ends  were  then  propped  up  from  the 
floor,  so  that  a  keyway  could  be  chipped  as  shown  by 
the  dotted  lines  F,  about  ij  inches  long,  J  inch  deep 
and  J  inch  wide,  in  both  halves,  thus  making  a  keyway 
3  x  J  x  J.  An  old  key  was  then  filed  to  fit.  When  in 
place  it  was  filed  to  the  same  level  as  the  shaft,  as 
shown.  A  cast-iron  bush  B  was  then  taken  in  halves, 

122 


TEMPORARY   REPAIR  TO   BROKEN  SHAFT 


123 


from  a  very  broad  pulley.  Then  two  pair  of  strong 
driving  clamps  E  E.  such  as  are  used  by  turners  for 
driving  large  shafts,  etc.,  when  turning,  were  procured. 
With  these  were  clamped  the  bushes  over  the  broken 
part,  thus  binding  the  whole  together.  For  a  quick 
repair  this  will  be  hard  to  beat,  as  the  shaft  was  stand- 
ing only  i  i  hours. 


XX 

HANDLING  MACHINERY  WITHOUT 
MARRING  IT 

COPPER  hammers  are  largely  used  for  driving  keys 
and  other  work  about  the  machinery.  When  new  a 
copper  hammer  is  soft  but  hardens  rapidly  with  use, 
so  that  after  short  service  it  will  bruise  work  nearly 
as  much  as  steel.  The  only  remedy  is  to  take  out  the 
handle  and  anneal  it  every  time  it  is  used. 

A  better  plan  is  to  use  a  babbitt  or  lead  hammer. 
If  made  of  lead  simply,  they  get  out  of  shape  quickly. 
To  prevent  this  take  a  piece  of  copper  pipe,  iron  pipe 
size,  and  drill  a  hole  in  the  center  for  handle  and  fill  it 
with  lead.  This  will  keep  its  shape. 

A  better  plan  still  is  to  use  hardwood  blocks  on  end. 
These  can  be  used  to  put  against  the  part  to  be  driven 
and  hit  with  a  hammer,  or  larger  blocks  can  be  used 
by  striking  on  end  with  simply  the  blocks  themselves. 

Blocks  4  to  5  inches  square  and  2j  to  3  feet  long 
are  handy  on  large  engines  for  driving  the  stub  endx)f 
connecting-rods  back  and  forth  when  keying  up. 

Altogether  too  many  people  handle  finished  machin- 
ery with  steel  bars.  The  ordinary  man  will  put  a  bar 
against  a  polished  part  or  against  a  bearing  and  bruise 
it  beyond  repair.  I  have  known  a  piece  of  8-inch  shaft 

124 


HANDLING   MACHINERY 


I25 


with  four  bearings  on  it,  all  nicely  skidded  for  handling 
that  had  long  indentations  made  on  every  bearing  by 
bars  being  placed  against  them  instead  of  against  the 
skids. 

Where  machinery  is  to  be  moved  it  pays  to  have 
wooden  levers  made  as  in  the  sketch.  Fig.  79.    These 


WOODEN  I-EVER. 

FIG.  79 

should  be  made  from  maple,  the  square  part  4x6 
inches  and  9  to  10  feet  long.  After  a  short  experience 
one  man  can  do  more  with  them  than  two  or  three  can 
with  a  bar.  They  will  do  a  great  deal  of  the  work 
usually  done  with  a  jack  and  will  have  it  all  done 
before  a  jack  could  be  gotten  into  position. 

When  using  wooden  blocks  and  levers  they  should 
be  kept  clean,  but  it  is  always  good  practice  to  strike 
them  on  end  on  some  solid  substance  before  using  to 
jar  off  any  loose  dirt  that  may  have  become  attached 
to  them. 


XXI 

TO  FIND  DEAD  CENTER 

ON  all  engines  when  preparing  to  set  the  valves,  the 
first  thing  to  look  after  is  to  find  and  adjust  all  lost 
motion  in  valve  gear,  then  proceed  to  place  the  engine 
on  the  "dead  center." 

Owing  to  the  fact  that  the  crosshead  will  remain 


FIG.   80 

stationary  a  short  time  before  the  crank-pin  passes 
the  center  and  remain  so  until  the  crank  has  passed 
the  center  a  short  distance,  it  is  best  to  take  greater 
care  than  to  simply  note  the  point  where  the  crosshead 
rests  at  end  of  the  stroke,  in  order  to  find  "dead 
center."  The  process  illustrated  in  Fig.  80  is  an 
accurate  process. 

In   the  figure  /  and   K  represent   two  crosshead 
126 


TO   FIND   DEAD   CENTER  127 

guides,  L  the  crosshead,  M  the  path  of  crank  travel, 
N  and  0  the  center  lines  of  connecting  rod  at  different 
positions,  and  P  the  balance  wheel. 

To  start  with,  make  a  tram  5  out  of  any  material 
convenient,  preferably  round  steel.  Turn  engine  around 
till  crank  is  at  point  B,  at  any  point  where  the  cross- 
head  is  still  moving  with  the  other  parts,  near  the  end 
of  the  stroke.  Then  mark  A  on  the  crosshead  running 
the  mark  up  close  to  nearest  or  most  convenient  guide 
bar.  (Where  crosshead  is  down  in  frame  of  engine, 
use  a  straight  edge  across  the  top  of  the  holding-down 
bars.)  Then  mark  C  on  guide  bar  opposite  mark  A 
on  the  crosshead.  Now  with  tram  S  (one  point  on 
given  mark  on  the  floor  opposite  fly-wheel  and  on  a 
line  with  one  edge  of  the  rim)  scribe  mark  D  on  the 
face  or  side  of  the  rim,  making  the  arc  come  to  edge  in 
either  case. 

Next>  turn  engine  so  that  the  crank  passes  the  center 
and  the  mark  A  on  the  crosshead  again  comes  to 
mark  C  on  the  guide  bar. 

Then  take  tram,  again  resting  it  on  the  same  point 
on  the  floor  and  scribe  arc  to  mark  F  on  same  edge  of 
rim  of  wheel.  The  crank  will  then  be  at  E. 

Now  place  prick  punch  marks  as  near  edge  as  pos- 
sible at  points  D  and  F  and  with  a  pair  of  dividers, 
bisect  the  distance  from  D  to  F  and  make  mark  G. 

Turn  the  engine  back  so  that,  with  the  tram  resting 
at  same  point  on  the  floor,  the  other  point  of  tram 
will  touch  G. 

The  crank  will  then  be  on  "dead  center"  at  /  and 
the  mark  A  on  the  crosshead  will  be  opposite  mark  H 


128  KNOCKS  AND   KINKS 

on  guide  bar,  which  you  will  now  mark  as  the  point 
where  crosshead  reaches  end  of  stroke. 

Turn  the  engine  to  the  opposite  end  of  stroke  and 
repeat  the  foregoing  moves  and  you  will  then  have 
both  "dead  centers"  found  and  marked. 

Now,  with  a  marking  chisel,  go  over  all  scribe  marks 
and  make  them  permanent  and  where  the  center  punch 
marks  are  on  rim  of  wheel,  the  floor  and  frame,  it  is  a 
wise  precaution  to  place  marks  with  chisel  around  the 


FIG.  8l 

center  punch  marks  thus  ["•"[.     It  is  also  a  good  means 
of  finding  your  marks  in  future. 

NOTE:  In  some  cases  there  is  no  fly  or  balance 
wheel  or  it  is  not  convenient  to  tram  to  them  for 
marking.  If  so,  the  rim  of  the  crank  disk  or  even  the 
surface  of  the  shaft  will  do.  The  further  you  get  from 
the  shaft  center,  the  better  however. 
The  next  move  is  to  get  the  eccentric  "dead  center." 
Where  the  eccentrics  are  fastened  by  set-screws, 
friction  keys  or  keys  easily  withdrawn,  loosen  up  on 
one  or  the  other  of  them  as  the  case  may  be  and  turn 
the  eccentric  around  the  shaft  while  finding  the  centers. 
Where  there  is  a  fixed  eccentric  such  as  governor 


TO   FIND   DEAD   CENTER  129 

eccentrics,  the  engine  itself  must  be  turned  around  to 
find  the  points  we  are  after. 

Make  a  tram  A,  Fig.  81,  out  of  a  board  or  sheet 
steel  and  place  at  point  indicated  a  nail  or  some  pointed 
piece  of  iron  or  steel,  just  far  enough  out  so  that  you 
can  scribe  arcs  B,  C  and  D,  E,  bringing  the  arcs  down 
to  the  edge  of  the  eccentric  at  points  B  and  D. 

Be  careful  in  using  the  tram,  to  have  the  end  on 


shaft  or  boss  of  eccentric  the  same  distance  away 
from  eccentric  in  both  instances. 

Take  a  pair  of  dividers  and  from  points  B  and  D, 
scribe  arcs  so  that  they  will  exactly  intersect  on  the 
eccentric  edge  at,  F.  This  will  be  the  center  line  of 
eccentric. 

Make  another  tram  G,  Fig.  82,  make  mark  H  with 
center  punch  on  eccentric  rod  and  with  one  leg  of 
tram  on  point  H  scribe  arcs,  /,  K,  and  L,  M,  on  the 
eccentric-strap  coming  to  points  /  and  L  on  the  edge 
of  strap. 

With  the  dividers  scribe  from  points  /  and  L  arcs 
exactly  intersecting  each  other  at  point  N._ 

With  marking  chisel,  make  permanent  marks  at 
point  F  on  the  eccentric  and  point  N  on  the  eccentric- 


I30  KNOCKS  AND   KINKS 

strap.  Bring  the  eccentric  around  so  that  both  points 
correspond  and  you  have  the  eccentric  on  one  "dead 
center/' 

From  points  /  and  L  scribe  arcs  0,  P  and  Q,  R, 
ending  at  points  O  and  Q  on  edge  of  strap,  from  points 
O  and  Q,  scribe  arcs  intersecting  at  point  S  on  the 
edge  of  strap.  With  chisel,  make  mark  on  strap  at  5. 
Bring  eccentric  around  so  that  point  F  corresponds 
with  point  5  and  you  have  the  eccentric  on  the  opposite 
end  of  travel. 


INDEX 

PAGE 

Accident  to  stuffing-box    102 

Adjusting  quarter-boxes   76 

Babbitt  hammers 124 

Bearing  caps,  vertical  engine,  setting     6 

dry,  cause  of  knocks 9 

heating  of    84 

oiling    2 

Bed,  cracked,  repairing 1 18 

Blocks,  hardwood    1 24 

Bolts,  holding-down,  too  short    .  . 102 

Boxes,  engine,  re-babbitting    82 

Brasses,  connecting-rod,  cause  of  knock   23 

Broken  shaft     1 1 1 

Causes  of  knocks  i,  3,  n,  21,  31 

Center,  dead,  finding  1 26,  1 28 

Centering  piston-rod  ., 49 

Chattering  on  seats,  valves  15 

Clearance  between  cranks  and  bearings,  cause  of  knock 26 

between  shaft  and  top  bearing,  vertical  engine 5 

top  slide  and  crosshead,  horizontal  engine  5 

determining     52 

in  cylinder,  cause  of  knock  25 

Compound  circulating  pump,  trouble  with  113 

Connecting-rod  brasses,  cause  of  knock  23 

-rod,  keeping  wedge  in  place  on  crosshead  end  117,  118 

Copper  hammers 1 24 

Core  sand  in  cylinder 75 

Crack  in  bed,  repairing  118 


132  INDEX 

PAGE 

Crank  end,  pound  on    95 

-pin  boxes,  heating    87 

cause  of  knock  22 

flat    46 

heating  of    84 

keying  up    •  84 

knocking  of     32 

loose    44,  90 

out  of  line  with  disk   43 

turning  device    64,  68 

Crosshead  end  of  connecting-rod,  keeping  wedge  in  place  ....  117,  118 

knocking  at     47 

out  of  line   48 

pin  cause  of  knock    23 

shoes,  adjustment    5 

bolting   1 1 6 

Curing  noisy  piston  valve     105 

Cylinder  clearance,  cause  of  knock    25 

core  sand  in 75 

design,  cause  of  knock    21 

detecting  knock  in  18 

noises     28 

not  in  line  with  slide     20 

out  of  line   48 

repairing    71 

Dead  center,  finding   1 26,  1 28 

Deflection  of  shaft           21 

Determining  clearance    52 

location  of  piston  25 

Diagrams,  indicator 3 

Dixie 64 

Dry  bearings,  cause  of  knock    9 

Eccentric  dead  center   1 28 

-rod    .  6 


INDEX  133 

PAGE 

Eccentric-strap,  taking  up    6 

Effect  of  inertia  of  moving  parts    55 

of  lead    59 

Elbow 99 

Emergency  repairs in 

Engine,  horizontal,  clearance  between  crosshead  and  slide    ...  4 

"out  of  line,"  cause  of  knocks    18 

repairs   .  .  .  .  : 116 

valves,  adjustment 3 

vertical,  clearance  between  shaft  and  top  bearing 5 

Escapes,  narrow     93 

Exhaust  main   99 

valve,  knock   13 

Flat  crank-pin 46 

Fly-wheel,  knock  in     62 

-wheel,  loose  .  .  26,  54 

Governors,  shaft,  knocks  in     8 

Griggs,  Eugene  L 78 

Grinding  out  grooves  in  valve     99 

Hammers,  babbitt    124 

copper    124 

lead    1 24 

Handling  machinery  without  marring    124 

Hardwood  blocks 1 24 

Head  end,  pound  on 93 

Heat  in  crank-pin  boxes     87 

Heating  of  bearings     84 

of  crank-pins    84 

Holding-down  'bolts  too  short    102 

Hollow  arms  and  brackets  intensify  sound  of  knocks     7 

Horizontal  engine,  clearance  between  crosshead  and  slide     ...  4 

Indicator  diagrams    3 


I34  INDEX 

PAGE 

Indicator,  using   3 

Inertia  of  moving  parts,  effect     55 

Jam-nut,  cause  of  knock    17 

Junk  ring,  cause  of  knock  17 

Kavanagh,  William   97,  105 

Keying  up  connecting-rod,  cause  of  knock 24 

up  crank-pins 84 

Kinks,  practical    97 

Knocking  at  crosshead 47 

of  crank-pin    32 

Knocks  caused  by  valves  lifting  from  seats 12 

causes i,  3,  n,  21,  31 

curious 61 

in  shaft  governors    8 

valve-gear    6 

Larson,  C.  J ^ i,  n,  21 

Lead,  effect     59 

hammers     1 24 

Levers,  wooden 125 

Lifting  from  seats,  valves     12 

Loose  crank-pin  44,  90 

fly-wheel    26,  54 

piston,  cause  of  knock    15 

Lost  motion,  taking  up  in  marine  engines 78 

Lubrication,  proper 88 

Machinery,  handling  without  marring 124 

Main,  exhaust    99 

Marine  engine    6 

practice    78 

Narrow  escapes    93 

Noises  in  cylinder 28 


INDEX  135 

PAGE 

Oil    88 

Oiling  bearings     2 

Packing  rings,  cause  of  knock    n,  17,  30 

Pin,  crosshead,  cause  of  knock   23 

Piston,  determining  location    25 

loose,  cause  of  knock     15 

-nut  wrench    70 

-ring,  setting   .' 51 

-rod,  centering    49 

long,  turning  on  short  lathe     69 

removing  from  crosshead    74 

substitute     97 

turning  and  refitting   64 

-valve  adjustment,  cause  of  knock   . n 

knock  in    n 

noisy,  curing .- 105 

Pop  safety  valve 99 

Practical  kinks   97 

Pressure  increased  in  cylinder,  cause  of  knock    6 

reduced,  cause  of  knock 10 

Pump,  compound  circulating,  trouble  with 113 

Quarter-boxes,  adjusting    76 

Re-babbitting  large  engine  boxes    82 

Reducing  valves 98 

Refitting  pistons 64 

Remedies  for  knocking  crank-pin     38 

Removing  tight  piston-rod  from  crosshead    74 

Repairing  crack  in  bed 1 18 

cylinder    71 

Repairs,  emergency in 

engine    116 

temporary,  to  broken  shaft 122 

Rigging  up  to  turn  and  refit  pistons 64 


136  INDEX 

PAGE 

Ring,  junk,  cause  of  knock   xy 

packing,  cause  of  knock n,  17,  30 

Rush  jobs    m 

Safety  valve,  pop   99 

Shaft,  broken    m 

deflection  '21 

governors,  knocks    8 

out  of  right  angles  with  cylinder     18 

temporary  repair    122 

Shoes,  crosshead,  adjustment    5 

crosshead,  bolting 1 16 

Side-knock  at  crosshead  pin 23 

Slide-valve,  adjustment,  cause  of  knock    1 1 

Spoke  of  fly-wheel,  knock  in   61 

Studs,  valve,  breaking    113 

Stuffing-box,  accident  to     102 

Substitute  piston-rod 97 

Temporary  repair  to  shaft  122 

Testing  for  loose  crank-pin    90 

Tight  piston-rod,  removing  from  crosshead    74 

Turning  long  piston-rods  on  a  short  lathe    69 

pistons   64 

Valve  adjustment  3 

chattering  on  seat 15 

error  in  setting  4 

-gear,  knocks 6 

grooves,  grinding  out  99 

lifting  from  seat,  cause  of  knock 12 

piston,  curing  noise  in  105 

reducing  98 

studs,  breaking  113 

Vertical  engine,  clearance  between  shaft  and  top  bearing 5 


INDEX  137 

PAGE 

Wakeman,  W.  H 90,  93 

Wear  on  piston  and  cylinder 20 

Wedge,  keeping  in  place  on  crosshead  end  of  connecting-rod .  .117,  118 

Wooden  levers    125 

Wrench,  piston-nut   70 


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